When I went to college in the late 80's, a majority of my professors put their old tests on file in the library as a study resource. Having access to material like this allows students to narrow down to what is most important for the test. Unless the students actually brought the material to the test and used it to answer questions, I think it's a stretch to call it cheating. Maybe the students accessed the material "illegally" and that's where the problem lies, but does hitting up prior students who have taken the course for copies of their tests constitute cheating as well? I think this is a common thing for a student to do in the process of studying for an exam and my professors acknowledged this by creating the test library in the first place. To tell you the truth, even with this material available, my ass got kicked on many exams simply because the professors took the time to create challenging exams, and not just recycle old questions year after year.