diff --git a/tracing-subscriber/src/layer.rs b/tracing-subscriber/src/layer.rs
index 39b5679972..346d7890c8 100644
--- a/tracing-subscriber/src/layer.rs
+++ b/tracing-subscriber/src/layer.rs
@@ -736,6 +736,9 @@ where
             return outer;
         }
 
+        // The intention behind calling `inner.register_callsite()` before the if statement
+        // is to ensure that the inner subscriber is informed that the callsite exists
+        // regardless of the outer subscriber's filtering decision.
         let inner = self.inner.register_callsite(metadata);
         if outer.is_sometimes() {
             // if this interest is "sometimes", return "sometimes" to ensure that