It's rare to see terms of use that are all actively enforced. I think it makes sense to state the outlines to justify e.g. banning a user, or in potential legal matters (IANAL, just assuming).
True, but it still enhances uncertainty for users - if you uploaded trade secrets, malware, etc you already had that uncertainty, now you also have it for whether your code will be deemed too high a percent AI, when you thought it was only ~1/3 AI or whatever.
Using any AI code is a risk of ban on codeberg. Just write it yourself and no one can say it's written by AI.