Anecdotally, as someone who's been starting to get more and more agent-only/driven PRs, a good amount of the time it's by an account with little to no activity until one day they suddenly start doing 50-100+ PRs a _day_ on entirely unrelated projects... you can kind of guess what they're doing.

As for motive, it probably varies, though some will loudly put that they're some agent manager or something with lots of contributions, so you can guess their motivations there.

In other cases, these are instrad brand-new accounts which is a related but I guess slightly different story... not gonna say these are spam bot accounts being juiced with fake activity but well...

These are all fair observations, I have not personally come across these yet but I am also not looking for them. I guess someone more involved in open source collaboration would have a better lens here.