I know I wouldn't risk selling a study guide that had anything in the same ballpark as answers to assignments.

Thanks to a quick google, here's my old student handbook: "Selling academic assignments. No person shall sell or offer for sale to any person enrolled at the University at Buffalo any academic assignment, or any inappropriate assistance in the preparation, research, or writing of any assignment, which the seller knows, or has reason to believe, is intended for submission in fulfillment of any course or academic program requirement."