Comment by mnahkies

I think the litmus test is roughly "is this obviously AI created" - if it's a well crafted PR that doesn't do the things you mention, and solves a genuine issue in a sensible way then you'd not be able to tell.

The other part of the litmus test is "does the person submitting actually understand what they're submitting and why" - which is arguably not required for PRs that you'd otherwise accept, but since you have to put time and effort into determining whether a given contribution is ok to merge, it's common decency for the submitter to have done a self review first (AI or no AI)