@JochenGlueck I am often reminded of Pascal's apology for having written a long letter, because he did not have time to write a short one.

@Lerner OK, that makes more sense then -- your comments led me to think you were repeatedly emailing her despite receiving no reply at all.

@Lerner there's nothing wrong with asking a first time, but repeatedly emailing this person may start to cross over into harassment.

If you're having the students grade each others' work, then I certainly hope that grade is purely for self-evaluation, and not factored into any kind of final letter grade.

Indeed, I didn't mean to imply that you were calling it widespread. Since it holding in "at least a few graduate schools" is at least consistent with the practice being widespread, and since I also don't know how widespread the practice was prior to my own grad school experience, I figured it was worth chiming in.

Speaking only to your last paragraph, as someone who completed a mathematics PhD in 2014, I have never heard of graduate students auditing every advanced course before taking them for credit. I have no data to back this up but I'd be very surprised if this was a widespread practice.

@NateEldredge - that's a good point and one I hadn't been aware of. Gaurav and JaapEldering's amended solution might be better, then.

Ah, I got the impression that the "I met" was recent.

Seems to me that the person you met would be a good person to ask.