I thought long and hard about this one because the first situation that popped into my head was one involving 2 teachers. They were really good friends and had a chat window open on both of their computers during a class period. One teacher complained to the other that their students were a bunch of jerks, etc. And the other teacher chimed in about his class, too. We'll, the reason I know the story is be a use a student took a picture of the conversation (he somehow was behind the teacher's desk and saw it)and shared it on social media. The teachers ended up on administrative leave, they lost the respect of many students, parents, etc. and learned a hard, but valuable lesson. The student that shared all that information received consequences, too for his actions. It was a very ugly time for all involved.