I usually get this out first day of class. I tell students that I like to run a mostly informal class and I encourage a free spirited learning enviroment. BUT, I tell them if I catch them cheating, they will fail. I tell them that if they cheat in here (the classroom) the will cheat out there (in the world),and the last thing we need in the world are more cheaters. This usually works and I have no problems.
