I find this pretty reasonable if you're interviewing with a handful of companies but I remember doing 20+ interviews in 2-3 weeks in university and would simply not have time for that.
I'm all for pounding the pavement if your network doesn't line you up, but 20+ in 2-3 weeks suggests a very different assembly-line approach. I'm having difficulty imagining how it would be logistically possible for me to line up 20-30 interviews in 2-3 weeks where I had predetermined that they were all places I wanted to work and could make my case. I would hope for a batting average and negotiating leverage where if I got in the door at a lot fewer places I would find something that worked.
