Add note on object permissions for FBVs (#5681)

Closes #3269

Author: carltongibson

docs/api-guide/permissions.md

@@ -192,7 +192,7 @@ If you need to test if a request is a read operation or a write operation, you s
 
 ---
 
-**Note**: The instance-level `has_object_permission` method will only be called if the view-level `has_permission` checks have already passed. Also note that in order for the instance-level checks to run, the view code should explicitly call `.check_object_permissions(request, obj)`. If you are using the generic views then this will be handled for you by default.
+**Note**: The instance-level `has_object_permission` method will only be called if the view-level `has_permission` checks have already passed. Also note that in order for the instance-level checks to run, the view code should explicitly call `.check_object_permissions(request, obj)`. If you are using the generic views then this will be handled for you by default. (Function-based views will need to check object permissions explicitly, raising `PermissionDenied` on failure.)
 
 ---