I took a number of university classes where I could have taught the class and where I probably knew more than the professor. Other classes I was able to get credit for based on work experience and demonstrated knowledge (to the above professor), but I needed to take two or three classes to demonstrate that I knew the material. As I recall, the university said they'd let me skip all relevant classes if my employer wrote them a letter confirming my work experience, if I took two or three related classes and got A's, and if the professors of those classes were convinced that I would gain nothing from taking additional similar classes.

So just because someone is taking a class doesn't mean he or she doesn't actually already know the material being "taught."

That said, I never tricked a professor.

Regards,
Craig Steiner