diff --git a/src/i18n/de-DE/gameMode/viewingRate.ts b/src/i18n/de-DE/gameMode/viewingRate.ts
index c368748..d793284 100644
--- a/src/i18n/de-DE/gameMode/viewingRate.ts
+++ b/src/i18n/de-DE/gameMode/viewingRate.ts
@@ -1,6 +1,7 @@
 export default {
   title: 'Einschaltquote',
 
+  controllersReady: '{count} Controller bereit!',
   currentlyViewing: 'Aktuell eingeschaltet',
   totalWatchRate: 'Totale Einschaltquote',
 
@@ -24,5 +25,12 @@ export default {
     action: {
       ok: 'Ok',
     },
+
+    error: {
+      newController: {
+        message: 'Neue Controller sind vom diesem Spiel ausgeschlossen!.',
+        caption: 'Controller: ',
+      },
+    },
   },
 };
diff --git a/src/i18n/en-US/gameMode/viewingRate.ts b/src/i18n/en-US/gameMode/viewingRate.ts
index a65b6f2..5c491f1 100644
--- a/src/i18n/en-US/gameMode/viewingRate.ts
+++ b/src/i18n/en-US/gameMode/viewingRate.ts
@@ -1,6 +1,7 @@
 export default {
   title: 'Viewing Rate',
 
+  controllersReady: '{count} controllers ready!',
   currentlyViewing: 'Currently viewing',
   totalWatchRate: 'Total viewing rate',
 
@@ -25,4 +26,11 @@ export default {
       ok: 'Ok',
     },
   },
+
+  error: {
+    newController: {
+      message: 'New controllers are excluded from this game.',
+      caption: 'Controller: ',
+    },
+  },
 };
diff --git a/src/pages/gameModes/ViewingRateGamePage.vue b/src/pages/gameModes/ViewingRateGamePage.vue
index bcff6fb..5ddbbee 100644
--- a/src/pages/gameModes/ViewingRateGamePage.vue
+++ b/src/pages/gameModes/ViewingRateGamePage.vue
@@ -25,7 +25,7 @@
           >
             <a class="text-h6">
               {{
-                t('gameMode.stopwatch.controllersReady', {
+                t('gameMode.viewingRate.controllersReady', {
                   count: settings.readyCheck
                     ? gameState.controllersReady.length
                     : controllers.length,
@@ -433,10 +433,21 @@ const runningListener = transition('running', (state, event: ButtonEvent) => {
   }
 
   const controllerId = event.controller.id;
-  const changes = { ...state.changeTimes };
-  if (!(controllerId in changes)) {
-    changes[controllerId] = [];
+
+  // Ignore controllers that connected after the start.
+  // This is to ensure correct calculation.
+  if (!(controllerId in state.changeTimes)) {
+    quasar.notify({
+      message: t('gameMode.viewingRate.error.newController.message'),
+      caption:
+        t('gameMode.viewingRate.error.newController.caption') +
+        event.controller.name,
+      color: 'negative',
+    });
+    return;
   }
+
+  const changes = { ...state.changeTimes };
   changes[controllerId].push(time.value);
 
   event.controller.setLight(isControllerViewing(state, event.controller.id));