diff --git a/channels/generic/websockets.py b/channels/generic/websockets.py
index b7a0250..3e77e3b 100644
--- a/channels/generic/websockets.py
+++ b/channels/generic/websockets.py
@@ -46,7 +46,7 @@ class WebsocketConsumer(BaseConsumer):
         # Ordering decorators
         if self.strict_ordering:
             return enforce_ordering(handler, slight=False)
-        elif self.slight_ordering:
+        elif getattr(self, "slight_ordering", False):
             raise ValueError("Slight ordering is now always on. Please remove `slight_ordering=True`.")
         else:
             return handler