I took a physics class that was so large that it filled 3 stadium-style rooms.....
This was the same guy who kept a database of every paper he received and had a program that would compare your paper vs. all the old ones to see how likely it was you'd plagiarized.
Now that I'm out of the business I can say this: If you're forced to take a class this large, you're justified in cheating. So little effort is being put into teaching you, why should you make any more effort back?
I'm not saying you SHOULD cheat - the consequences of getting caught are too bad, and anyway, probably the only way you might learn something in such a class is by doing some work on your own. But there's a reason the teacher of this class needed this database. Although it's probably no fault of his own (the size of the class is probably someone else's idea), he is violating some kind of unspoken contract between teacher and student, so of course students will violate it on their side.
Hooray to all of you who want to teach small classes at small colleges, but remember that the problem is: the academic job market is so bad that you might not have your choice.
PS: Lots of good (and amusing) advice on academic careers here:
http://chronicle.com/jobs/archive/advice/mentor.htmand also see the first person essays elsewhere on that site.