The only time I have been treated "rudely" by a CM was when it was part of the show, like in 50's prime time or WCC. (like when I was really thirsty at the WCC once and kept asking for more tea and the waiter said something like "What, have you got a wooden leg or something? Where are you putting all this tea?") Of course that's supposed to happen - that's why we go there!
But seriously, I've encountered CMs who didn't know what they were talking about, but that's understandable. But I have never been treated rudely by a CM. Nor have I seen a CM treat someone else rudely.
This is pretty amazing considering all the time I've spent there, and how many CM encounters I've had. I've never really thought about it before, but you would expect by the law of averages that I would have encountered someone who just had a really bad day, but no. And I'm really trying to think of something.
I can tell you plenty of stories about how CMs were really nice and went over and above for me, however. But that's for another thread.