Yes, "credits" indeed. To agencies or to the photographer personally changes nothing. One of the photographers to whom I talked was requesting credits be given to the client for whom he'd made the image.
 

You don't. Your claim that the practice is not standard is effectively disproved by exhibiting examples of major sites doing it. Your providing instances of sites which do not changes nothing.
 

I have absolutely not suggested giving any sort of guarantee whatsoever, which would obviously be both stupid and infeasible. I have suggested making our users aware of the fact that giving credits in this way can in some cases be a constructive behaviour.
I think that we see, too often, people removing credits on principle, which discourages valuable contributors and serves no purpose. I believe that people should be educated in considering whether this is necessary or benefitial. That is all.
 

Your first example (wetriffs) would not be a problem, in my opinion.
For your second example, we'd just refuse to run the credits. Once again, I never suggested that we guarantee credits, nor that giving credits should be systematic.
Incidentally, congratulations on your Godwin point.

-- Rama