So, get rid of formatting, throw in an innocent grammatical mistake, intentionally omit an obscure corner case while alluding to an existential crisis for taking compromises and you're good to go!
Too many PRs wouldn't be a problem if they were easily digestible: But they often include these giant refactors with confusing changes that aren't elaborated.
The real underlying problem is with authors who do not understand the code they submit. If you cannot defend the PR, you shouldn't be submitting it.
Will you submit an AI-generated pull request to OpenJDK? No? Voilà, you have successfully self-enforced the OpenJDK policy.
Or do you go to the trouble of finding an interesting issue to work on, get your agent to code it up, manually polish it to make it less AI-looking in case there are doubts, and then submit it? Yes? No. Why would you? To prove some kind of point, to yourself, that you can never disclose publicly? Most people have better things to do. Voilà, the policy is, again, self-enforced. Enjoy your day at the beach instead of trying to trick a project that is politely asking you not to trick it!