On the contrary, a small piece of text that says “this code deserves more review because humans may not have seen it” is absolutely necessary.

All this is doing is making it so I can hide that I didn’t touch the code.

Why are you assuming that everyone would honestly disclose AI use if it was a rule?

The honest ones that would disclose it to say "this needs more eyes, guys" can still do just that. The dishonest ones that would hide AI use will do exactly that whether it's a rule or not.

The only difference here is there's no punitive action to follow for non-disclosure because that would be a gigantic waste of time when, AI or not, all code needs to be reviewed anyway.