That assumes that proof of anything is required. That's not usually how college disciplinary actions work. At its worst, universities will sometimes assume a

That assumes that proof of anything is required. That's not usually how college disciplinary actions work. At its worst, universities will sometimes assume a student accused of wrongdoing is lying, and punish the student based solely on the word of the faculty/staff bringing the charge. This happens in lesser cases where the administration thinks it can get away with it, and when the student is frightened of harsher sanctions that might be inflicted if the student asserts his or her rights and demands a full hearing process. At its best (typically in more serious cases), the disciplinary process resembles a civil case (except instead of a jury, it's more of a tribunal) where the required proof is a preponderance of the evidence. It's no wonder 200 students confessed. If I was in that class and I'd never seen the test bank, I'd have confessed too. It's been my observation that the disciplinary process is better at railroading not-provably-guilty students than punishing provably-guilty students. I would not want to take my chances.