diff --git a/src/Core/Exception/NotFoundException.php b/src/Core/Exception/NotFoundException.php
index f0a1f3139ed6..e6ba2c5cbe59 100644
--- a/src/Core/Exception/NotFoundException.php
+++ b/src/Core/Exception/NotFoundException.php
@@ -22,5 +22,15 @@
  */
 class NotFoundException extends ServiceException
 {
-
+    /**
+     * Allows overriding message for injection of Whitelist Notice.
+     *
+     * @param string $message the new message
+     * @return void
+     * @access private
+     */
+    public function setMessage($message)
+    {
+        $this->message = $message;
+    }
 }
diff --git a/src/Core/GrpcRequestWrapper.php b/src/Core/GrpcRequestWrapper.php
index 3d89d417a9e0..51cb3a3f1a07 100644
--- a/src/Core/GrpcRequestWrapper.php
+++ b/src/Core/GrpcRequestWrapper.php
@@ -216,6 +216,7 @@ private function convertToGoogleException(ApiException $ex)
                 break;
 
             case Grpc\STATUS_NOT_FOUND:
+            case Grpc\STATUS_UNIMPLEMENTED:
                 $exception = Exception\NotFoundException::class;
                 break;
 
diff --git a/src/Core/GrpcTrait.php b/src/Core/GrpcTrait.php
index 46313151a373..01a655e3e5d9 100644
--- a/src/Core/GrpcTrait.php
+++ b/src/Core/GrpcTrait.php
@@ -19,9 +19,10 @@
 
 use DateTime;
 use DateTimeZone;
-use Google\Auth\FetchAuthTokenCache;
 use Google\Auth\Cache\MemoryCacheItemPool;
+use Google\Auth\FetchAuthTokenCache;
 use Google\Cloud\Core\ArrayTrait;
+use Google\Cloud\Core\Exception\NotFoundException;
 use Google\Cloud\Core\GrpcRequestWrapper;
 use google\protobuf;
 
@@ -31,6 +32,7 @@
 trait GrpcTrait
 {
     use ArrayTrait;
+    use WhitelistTrait;
 
     /**
      * @var GrpcRequestWrapper Wrapper used to handle sending requests to the
@@ -53,9 +55,10 @@ public function setRequestWrapper(GrpcRequestWrapper $requestWrapper)
      *
      * @param callable $request
      * @param array $args
+     * @param bool $whitelisted
      * @return \Generator|array
      */
-    public function send(callable $request, array $args)
+    public function send(callable $request, array $args, $whitelisted = false)
     {
         $requestOptions = $this->pluckArray([
             'grpcOptions',
@@ -63,7 +66,15 @@ public function send(callable $request, array $args)
             'requestTimeout'
         ], $args[count($args) - 1]);
 
-        return $this->requestWrapper->send($request, $args, $requestOptions);
+        try {
+            return $this->requestWrapper->send($request, $args, $requestOptions);
+        } catch (NotFoundException $e) {
+            if ($whitelisted) {
+                throw $this->modifyWhitelistedError($e);
+            }
+
+            throw $e;
+        }
     }
 
     /**
diff --git a/src/Core/RestTrait.php b/src/Core/RestTrait.php
index 663687a807e9..1640e5baad55 100644
--- a/src/Core/RestTrait.php
+++ b/src/Core/RestTrait.php
@@ -17,6 +17,8 @@
 
 namespace Google\Cloud\Core;
 
+use Google\Cloud\Core\Exception\NotFoundException;
+
 /**
  * Provides shared functionality for REST service implementations.
  */
@@ -24,6 +26,7 @@ trait RestTrait
 {
     use ArrayTrait;
     use JsonTrait;
+    use WhitelistTrait;
 
     /**
      * @var RequestBuilder Builds PSR7 requests from a service definition.
@@ -64,9 +67,10 @@ public function setRequestWrapper(RequestWrapper $requestWrapper)
      * @param string $resource The resource type used for the request.
      * @param string $method The method used for the request.
      * @param array $options [optional] Options used to build out the request.
+     * @param array $whitelisted [optional]
      * @return array
      */
-    public function send($resource, $method, array $options = [])
+    public function send($resource, $method, array $options = [], $whitelisted = false)
     {
         $requestOptions = $this->pluckArray([
             'restOptions',
@@ -74,12 +78,20 @@ public function send($resource, $method, array $options = [])
             'requestTimeout'
         ], $options);
 
-        return json_decode(
-            $this->requestWrapper->send(
-                $this->requestBuilder->build($resource, $method, $options),
-                $requestOptions
-            )->getBody(),
-            true
-        );
+        try {
+            return json_decode(
+                $this->requestWrapper->send(
+                    $this->requestBuilder->build($resource, $method, $options),
+                    $requestOptions
+                )->getBody(),
+                true
+            );
+        } catch (NotFoundException $e) {
+            if ($whitelisted) {
+                throw $this->modifyWhitelistedError($e);
+            }
+
+            throw $e;
+        }
     }
 }
diff --git a/src/Core/WhitelistTrait.php b/src/Core/WhitelistTrait.php
new file mode 100644
index 000000000000..5e40e6bef7a3
--- /dev/null
+++ b/src/Core/WhitelistTrait.php
@@ -0,0 +1,39 @@
+<?php
+/**
+ * Copyright 2017 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace Google\Cloud\Core;
+
+use Google\Cloud\Core\Exception\NotFoundException;
+
+/**
+ * Manages exceptions for requests which may have whitelist restrictions.
+ */
+trait WhitelistTrait
+{
+    /**
+     * Modify the error message of a whitelisted exception.
+     *
+     * @param NotFoundException $e The exception.
+     * @return NotFoundException
+     */
+    private function modifyWhitelistedError(NotFoundException $e)
+    {
+        $e->setMessage('NOTE: Error may be due to Whitelist Restriction. ' . $e->getMessage());
+
+        return $e;
+    }
+}
diff --git a/src/PubSub/Connection/Grpc.php b/src/PubSub/Connection/Grpc.php
index 445c7a6be946..903de3fc860e 100644
--- a/src/PubSub/Connection/Grpc.php
+++ b/src/PubSub/Connection/Grpc.php
@@ -288,10 +288,11 @@ public function acknowledge(array $args)
      */
     public function listSnapshots(array $args)
     {
+        $whitelisted = true;
         return $this->send([$this->subscriberClient, 'listSnapshots'], [
             $this->pluck('project', $args),
             $args
-        ]);
+        ], $whitelisted);
     }
 
     /**
@@ -299,11 +300,12 @@ public function listSnapshots(array $args)
      */
     public function createSnapshot(array $args)
     {
+        $whitelisted = true;
         return $this->send([$this->subscriberClient, 'createSnapshot'], [
             $this->pluck('name', $args),
             $this->pluck('subscription', $args),
             $args
-        ]);
+        ], $whitelisted);
     }
 
     /**
@@ -311,10 +313,11 @@ public function createSnapshot(array $args)
      */
     public function deleteSnapshot(array $args)
     {
+        $whitelisted = true;
         return $this->send([$this->subscriberClient, 'deleteSnapshot'], [
             $this->pluck('snapshot', $args),
             $args
-        ]);
+        ], $whitelisted);
     }
 
     /**
@@ -327,10 +330,11 @@ public function seek(array $args)
             $args['time'] = (new protobuf\Timestamp)->deserialize($time, $this->codec);
         }
 
+        $whitelisted = true;
         return $this->send([$this->subscriberClient, 'seek'], [
             $this->pluck('subscription', $args),
             $args
-        ]);
+        ], $whitelisted);
     }
 
     /**
diff --git a/src/PubSub/Connection/Rest.php b/src/PubSub/Connection/Rest.php
index 44bbb65e7fcc..d45e9b4b2d15 100644
--- a/src/PubSub/Connection/Rest.php
+++ b/src/PubSub/Connection/Rest.php
@@ -214,7 +214,8 @@ public function acknowledge(array $args)
      */
     public function listSnapshots(array $args)
     {
-        return $this->send('snapshots', 'list', $args);
+        $whitelisted = true;
+        return $this->send('snapshots', 'list', $args, $whitelisted);
     }
 
     /**
@@ -222,7 +223,8 @@ public function listSnapshots(array $args)
      */
     public function createSnapshot(array $args)
     {
-        return $this->send('snapshots', 'create', $args);
+        $whitelisted = true;
+        return $this->send('snapshots', 'create', $args, $whitelisted);
     }
 
     /**
@@ -230,7 +232,8 @@ public function createSnapshot(array $args)
      */
     public function deleteSnapshot(array $args)
     {
-        return $this->send('snapshots', 'delete', $args);
+        $whitelisted = true;
+        return $this->send('snapshots', 'delete', $args, $whitelisted);
     }
 
     /**
@@ -238,7 +241,8 @@ public function deleteSnapshot(array $args)
      */
     public function seek(array $args)
     {
-        return $this->send('subscriptions', 'seek', $args);
+        $whitelisted = true;
+        return $this->send('subscriptions', 'seek', $args, $whitelisted);
     }
 
     /**
diff --git a/tests/system/ServiceWhitelist/WhitelistTest.php b/tests/system/ServiceWhitelist/WhitelistTest.php
new file mode 100644
index 000000000000..cbb86b347cc7
--- /dev/null
+++ b/tests/system/ServiceWhitelist/WhitelistTest.php
@@ -0,0 +1,182 @@
+<?php
+/**
+ * Copyright 2017 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace Google\Cloud\Tests\System\Whitelist;
+
+use Google\Cloud\Core\Exception\NotFoundException;
+use Google\Cloud\Core\Timestamp;
+use Google\Cloud\PubSub\PubSubClient;
+
+/**
+ * @group whitelist
+ */
+class WhitelistTest extends \PHPUnit_Framework_TestCase
+{
+    const MESSAGE = 'NOTE: Error may be due to Whitelist Restriction.';
+    const TESTING_PREFIX = 'gcloud_whitelist_testing_';
+
+    private static $deletionQueue = [];
+    private $keyFilePath;
+
+    public function setUp()
+    {
+        if (!defined('GOOGLE_CLOUD_WHITELIST_KEY_PATH')) {
+            $this->markTestSkipped('Missing whitelist keyfile path for whitelist system tests.');
+        }
+
+        $this->keyFilePath = GOOGLE_CLOUD_WHITELIST_KEY_PATH;
+    }
+
+    public function testPubSubListSnapshotsRest()
+    {
+        $client = new PubSubClient([
+            'keyFilePath' => $this->keyFilePath,
+            'transport' => 'rest'
+        ]);
+
+        $this->checkException(function() use ($client) {
+            iterator_to_array($client->snapshots());
+        });
+    }
+
+    public function testPubSubListSnapshotsGrpc()
+    {
+        $client = new PubSubClient([
+            'keyFilePath' => $this->keyFilePath,
+            'transport' => 'grpc'
+        ]);
+
+        $this->checkException(function() use ($client) {
+            iterator_to_array($client->snapshots());
+        });
+    }
+
+    public function testPubSubCreateSnapshotRest()
+    {
+        $client = new PubSubClient([
+            'keyFilePath' => $this->keyFilePath,
+            'transport' => 'rest'
+        ]);
+
+        $topic = $client->createTopic(uniqid(self::TESTING_PREFIX));
+        self::$deletionQueue[] = function () use ($topic) {
+            $topic->delete();
+        };
+
+        $sub = $topic->subscribe(uniqid(self::TESTING_PREFIX));
+        self::$deletionQueue[] = function () use ($sub) {
+            $sub->delete();
+        };
+
+        $this->checkException(function () use ($client, $sub) {
+            $client->createSnapshot(uniqid(self::TESTING_PREFIX), $sub);
+        });
+    }
+
+    public function testPubSubCreateSnapshotGrpc()
+    {
+        $client = new PubSubClient([
+            'keyFilePath' => $this->keyFilePath,
+            'transport' => 'grpc'
+        ]);
+
+        $topic = $client->createTopic(uniqid(self::TESTING_PREFIX));
+        self::$deletionQueue[] = function () use ($topic) {
+            $topic->delete();
+        };
+
+        $sub = $topic->subscribe(uniqid(self::TESTING_PREFIX));
+        self::$deletionQueue[] = function () use ($sub) {
+            $sub->delete();
+        };
+
+        $this->checkException(function () use ($client, $sub) {
+            $client->createSnapshot(uniqid(self::TESTING_PREFIX), $sub);
+        });
+    }
+
+    public function testPubSubSeekRest()
+    {
+        $client = new PubSubClient([
+            'keyFilePath' => $this->keyFilePath,
+            'transport' => 'rest'
+        ]);
+
+        $topic = $client->createTopic(uniqid(self::TESTING_PREFIX));
+        self::$deletionQueue[] = function () use ($topic) {
+            $topic->delete();
+        };
+
+        $sub = $topic->subscribe(uniqid(self::TESTING_PREFIX));
+        self::$deletionQueue[] = function () use ($sub) {
+            $sub->delete();
+        };
+
+        $this->checkException(function () use ($sub) {
+            $sub->seekToTime(new Timestamp(new \DateTime));
+        });
+    }
+
+    public function testPubSubSeekGrpc()
+    {
+        $client = new PubSubClient([
+            'keyFilePath' => $this->keyFilePath,
+            'transport' => 'grpc'
+        ]);
+
+        $topic = $client->createTopic(uniqid(self::TESTING_PREFIX));
+        self::$deletionQueue[] = function () use ($topic) {
+            $topic->delete();
+        };
+
+        $sub = $topic->subscribe(uniqid(self::TESTING_PREFIX));
+        self::$deletionQueue[] = function () use ($sub) {
+            $sub->delete();
+        };
+
+        $this->checkException(function () use ($sub) {
+            $sub->seekToTime(new Timestamp(new \DateTime));
+        });
+    }
+
+    private function checkException(callable $call)
+    {
+        $thrown = false;
+        $ex = null;
+        try {
+            $call();
+        } catch (\Exception $e) {
+            $thrown = true;
+            $ex = $e;
+        }
+
+        $this->assertTrue($thrown);
+        $this->assertInstanceOf(NotFoundException::class, $ex);
+        $this->assertTrue(strpos($ex->getMessage(), self::MESSAGE) !== false);
+    }
+
+    public static function tearDownFixtures()
+    {
+        foreach (self::$deletionQueue as $toDelete) {
+            if (!is_callable($toDelete)) {
+                throw new \Exception('fixtures must be callables');
+            }
+
+            call_user_func($toDelete);
+        }
+    }
+}
diff --git a/tests/system/bootstrap.php b/tests/system/bootstrap.php
index f9e2b36a997c..528369062539 100644
--- a/tests/system/bootstrap.php
+++ b/tests/system/bootstrap.php
@@ -8,6 +8,7 @@
 use Google\Cloud\Tests\System\PubSub\PubSubTestCase;
 use Google\Cloud\Tests\System\Spanner\SpannerTestCase;
 use Google\Cloud\Tests\System\Storage\StorageTestCase;
+use Google\Cloud\Tests\System\Whitelist\WhitelistTest;
 
 if (!getenv('GOOGLE_CLOUD_PHP_TESTS_KEY_PATH')) {
     throw new \Exception(
@@ -15,6 +16,10 @@
     );
 }
 
+if (getenv('GOOGLE_CLOUD_PHP_TESTS_WHITELIST_KEY_PATH')) {
+    define('GOOGLE_CLOUD_WHITELIST_KEY_PATH', getenv('GOOGLE_CLOUD_PHP_TESTS_WHITELIST_KEY_PATH'));
+}
+
 register_shutdown_function(function () {
     PubSubTestCase::tearDownFixtures();
     DatastoreTestCase::tearDownFixtures();
@@ -22,4 +27,5 @@
     LoggingTestCase::tearDownFixtures();
     BigQueryTestCase::tearDownFixtures();
     SpannerTestCase::tearDownFixtures();
+    WhitelistTest::tearDownFixtures();
 });
diff --git a/tests/unit/Core/Exception/NotFoundExceptionTest.php b/tests/unit/Core/Exception/NotFoundExceptionTest.php
new file mode 100644
index 000000000000..72dd944a5f67
--- /dev/null
+++ b/tests/unit/Core/Exception/NotFoundExceptionTest.php
@@ -0,0 +1,36 @@
+<?php
+/**
+ * Copyright 2016 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace Google\Cloud\Tests\Unit\Core\Exception;
+
+use Google\Cloud\Core\Exception\NotFoundException;
+
+/**
+ * @group core
+ * @group exception
+ */
+class NotFoundExceptionTest extends \PHPUnit_Framework_TestCase
+{
+    public function testSetMessage()
+    {
+        $ex = new NotFoundException('hello');
+        $this->assertEquals($ex->getMessage(), 'hello');
+
+        $ex->setMessage('world');
+        $this->assertEquals($ex->getMessage(), 'world');
+    }
+}
diff --git a/tests/unit/Core/WhitelistTraitTest.php b/tests/unit/Core/WhitelistTraitTest.php
new file mode 100644
index 000000000000..dd654c205919
--- /dev/null
+++ b/tests/unit/Core/WhitelistTraitTest.php
@@ -0,0 +1,58 @@
+<?php
+/**
+ * Copyright 2016 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace Google\Cloud\Tests\Unit\Core;
+
+use Google\Cloud\Core\Exception\NotFoundException;
+use Google\Cloud\Core\Exception\ServiceException;
+use Google\Cloud\Core\WhitelistTrait;
+
+/**
+ * @group core
+ */
+class WhitelistTraitTest extends \PHPUnit_Framework_TestCase
+{
+    private $trait;
+
+    public function setUp()
+    {
+        $this->trait = new WhitelistTraitStub;
+    }
+
+    public function testModifyWhitelistedError()
+    {
+        $ex = new NotFoundException('hello world');
+
+        $res = $this->trait->call('modifyWhitelistedError', [$ex]);
+
+        $this->assertInstanceOf(NotFoundException::class, $res);
+        $this->assertEquals(
+            $res->getMessage(),
+            'NOTE: Error may be due to Whitelist Restriction. hello world'
+        );
+    }
+}
+
+class WhitelistTraitStub
+{
+    use WhitelistTrait;
+
+    public function call($method, array $args)
+    {
+        return call_user_func_array([$this, $method], $args);
+    }
+}