In the case of Microsoft Exams (at least when I took them a few years ago), I had the sense that there was an "arms race". Questions were made more difficult and obscure than they needed to be, in order to drive pass rates down...when the real issue was braindumps and more blatant forms of cheating in some parts of the world. Which creates more demand for braindumps.

I wouldn't be surprised if college instructors start doing this as well-make exams tougher to compensate for cheating, rather than dealing with cheating head-on.