New policy boils down to "AI or not, it's still your code and you're responsible for it". I can get on board with that.
A good thing about the "you're the author regardless of the tool you used to produce the code" policy is that if a developer repeatedly submits poor quality AI generated code, one does not blame the model or the agent, one bans/terminates the developer.
But, we have long had a stable social system for collaboration, and in particular dealing with low quality contributions. Mostly (or at least ideally) it involves taking some time to look at the contribution and provide some feedback. The time invested is not worth it on a single exchange basis, but it’s a repeat game, so you are investing in the future.
LLMs, and people willing to just spam crap they don’t really understand blows that all up.