As to your first question, there is a thread about someone getting banned:
As to your second question, I think as gamers we should think about how companies are banning paying customers. Right now as gamers we have no rights. A company like Blizzard can change the rules any second they want. I’ve been playing Hots since almost day 1. I love the game and it would suck if the rules change to a point where something I say in a match might get me banned.