only a disqualification from the round and that's it? if someone cheated because he will get a negative delta because of the wrong submission and not able to solve the problem at all during the contest. i saw codeforces just show "skipped" for that round and removes the ratings from his account for that round only but in the end it's not a punishment but a small gift for him as his ratings got no negative. one of my friend become a pupil using this trick couple of days ago. MikeMirzayanov