Also -- the ship has kinda sailed on this - maybe a @not_override would make more sense.

Isn't the goal to make sure you don't accidentally override a method? saying "I know I'm overriding this" is less useful than "I'm not intending to override anything here"

I think you're fighting a straw man. I never said @override should be added to the language. I said that it would be useful to have a 3rd party metaclass or a class decorator that implements it which packages may voluntarily use to constrain their subclasses (or their own uses -- different designs are possible).