Yeah, I'm also in this camp. Saying we are going to deny all AI-written code wholesale and then asking them to properly attribute AI-written code is just going to incentivize not quoting AI-written code. Another thing is that when they say "can answer questions about it," it's also non-barrier, because the person will just feed the questions into a LLM. Short of an in-person interview, I don't see how this is going to keep anyone but honest users of AI out of the code base. I guess it could also be used retrospectively as a basis to ban someone.

Nothing, but nothing did before LLMs became a thing. The test lies in whether the submitter can explain the code they submitted, and more importantly, the why.