Fully agree! It's more harmful on contributors and maintainers to let in AI contributions and take the discussion after on a per-contribution basis. We need the rules to be clear from the beginning.
Can people "cheat" and make AI contributions so precise, well-tested and minimal and *easy to maintain* that maintainers will think it's a genuine human contribution? I would worry about it when it happens. If people do this without declaration, they're on the wrong side of the line, anyway.