This was the only time I was threatened with a detention in high school. The Study hall proctor was my calc teacher (a waaaay cool guy)
Someone asked him a remedial math problem (reducing fractions). I offered to help...
I explained that when given a problem like:
All you really need to do is cross of the 6s
And it reduces to 1/4
The teacher looked up at me and said, "You know, I could put you away in detention for the rest of the school year for that..."
He then flashed a wicked grin and I explained to the student that this was not how math usually worked.
If you didn't get this... *grin* Oh well ;)