Hi T!!!!! I keep the lock at the handle on my Kelly's so there's minimal movement thus very, very little "smiley" action.....although on my Marron Kelly from the late 50's you can see a small smiley but that's only because the bag is so dang OLD! LOL!
I hang a heart cadena from the clochette on my Rouge H Birkin and so far, no smiley.
I think if you hang the cadena at the handle hardware, you should be just fine.........