I usually only see bell curves used here when it'll favor the students in some way. It would annoy the hell out of me if they were doing it in the scenario you describe. However, I also look up all my classes/teachers before taking them so I don't end up in a horrible situation. Maybe other profs do it here, and I just haven't taken classes with them. I'm not at an elite school though, and those can really be tricky. I know of some which practically require you to have already know the material before it's taught. Personally, I wouldn't go to one 'til grad school. No reason to ruin one's gpa as an undergrad.