It is enforceable. Not in all cases, probably not even in the majority, but it only needs a few examples to be hit with large fines and everyone doing legal things will take notice. Often you can find enough evidence to get someone to confess to using AI and that is aall the courts need.

Scammers of course will not put this in, but they are already breaking the law so this might be - like tax evasion - be a way to get scammers who you can’t get for something else.