Every halfway-decent project will have a near-infinite stream of enthusiastic teenagers willing to "contribute" by acting as a meat proxy for whatever LLM vendor happens to have a free trial tier of their bargain-bin model that week. How do you propose a project separates their PRs from genuinely valuable human-driven AI use?

Pre-LLM it used to be pretty obvious to reviewers which PRs were complete garbage, and which were worth actually reading. Post-LLM the two look identical at first glance, and it only becomes clear that something is garbage after investing a nontrivial amount of time into it. And reviewing is where the real bottleneck lies - not writing.

So if your project welcomes AI use, who is going to dig the diamonds out of the endless flow of slop? It sure is a great way to lose volunteers, and if you delegate all work to LLMs you no longer have a community.

Having a "we ban obvious AI use" policy means that the human is essentially asked to provide a proof-of-work. Want us to invest time in your PR? First demonstrate that you aren't a time-waster.