Yeah I have.. I remember in 11th grade Spanish glass, this kid named S walked in 20 minutes late apologized for his absence and lateness and handed the teacher a doctors note and silently went to his seat. The first thing she did after reading it was say, Gonorrhea eh? The class started laughing and this kid named Jonathan started cracking jokes.. and this kid was so embarrassed, and he looked like he was going to cry.. I told Jonathan to shut up and he wouldn't so when he started tilting his seat back, I saw a textbook on the floor and kicked it at his chair causing him and his chair to fall and him bumping his head on the desk on the way down. The class roared when he fell.
I asked the teacher if it was really necessary that she'd say that out loud embarrassing him like that.. and when she got nasty with me saying that if he wasn't late it wouldn't have happened and threatened to call the dean because I disrupted the class, I told her to go ahead, and asked her how she'd feel if someone let it slip that she was sleeping with both the gym teacher and the janitor and if her husband (who was the dean) knew that she wasn't sure who the father of her unborn kid was.. I said it must suck to be her since she knows that her husband couldn't possibly be the father and kids, especially those that don't like her like to gossip and some of those kids happen to work in the deans office next period. I asked her just who does she think the dean will listen to.. the kids he trusts enough to work in his office, or her. She apologized to S for what she did.