That said, requiring adequate disclosure of AI is just fair. It also suggests that the other side is willing to accept AI-supported contributions (without being willing to review endless AI slop that they could have generated themselves if they had the time to read it).
I would expect such a maintainer to respond fairly to "I first vibecoded it. I then made manual changes, vibecoded a test, cursorily reviewed the code, checked that the tests provide good coverage, ran both existing and new tests, and manually tested the code."
That fair response might be a thorough review, or a request that I do the thorough review before they put in the time, but I'd expect it to be more than a blatant "nope, AI touched this, go away".