diff --git a/src/validate/html/validateEventHandler.js b/src/validate/html/validateEventHandler.js
index 3c0f1f288d..634f8729da 100644
--- a/src/validate/html/validateEventHandler.js
+++ b/src/validate/html/validateEventHandler.js
@@ -31,5 +31,5 @@ export default function validateEventHandlerCallee ( validator, attribute ) {
 		message += `. '${callee.name}' exists on 'helpers', did you put it in the wrong place?`;
 	}
 
-	validator.error( message, start );
-}
\ No newline at end of file
+	validator.warn( message, start );
+}
diff --git a/test/validator/samples/method-nonexistent-helper/errors.json b/test/validator/samples/method-nonexistent-helper/warnings.json
similarity index 100%
rename from test/validator/samples/method-nonexistent-helper/errors.json
rename to test/validator/samples/method-nonexistent-helper/warnings.json
diff --git a/test/validator/samples/method-nonexistent/errors.json b/test/validator/samples/method-nonexistent/warnings.json
similarity index 100%
rename from test/validator/samples/method-nonexistent/errors.json
rename to test/validator/samples/method-nonexistent/warnings.json
diff --git a/test/validator/samples/window-event-invalid/errors.json b/test/validator/samples/window-event-invalid/warnings.json
similarity index 100%
rename from test/validator/samples/window-event-invalid/errors.json
rename to test/validator/samples/window-event-invalid/warnings.json