@Sven Groot: No one said being a teacher is easy, I think they are underpaid and undervalued (same thing). I have massive respect for all coaches and teachers out there.
The DMV is a good example because there is no interpretation to traffic regulations. If you come from the right, you have right of way. You need to memorize that. And that way of testing is excellent.
The DMV test was an example of a test you cant cheat at. So you wouldnt need to prevent it. Sure you can look over your shoulder at the other guy, but because of the time constraint you would run behind hoplessly (seen it happen).
Let me adjust my point then to something we can agree on, I often formulate my opinion a bit to harsh, I'm working on that;
Instead of trying to prevent cheating, put that energy into designing tests so that is in the students best interest to learn and master the skill being tested.
A written exam is easy to make and grade, it's also easy to cheat at.