I've been accused of this same thing with some of the exams I have given in the past. I'll assume that most instructors probably have. Sometimes the complaints

I've been accused of this same thing with some of the exams I have given in the past. I'll assume that most instructors probably have. Sometimes the complaints are justified, and sometimes I believe that the students have just not prepared well. Even without mass protests, I will sometimes notice that a significant fraction of students performed poorly on one or more questions/sections, and take that as an indication that I have either not covered that unit's material as well as in the past, or that I have asked the question(s) in a way that was unclear. I can't say whether or not this exam was fair, but I can say that if 90% of students make similar complaints, that I would have to take a hard look at the way I had managed the course prior to the exam.