If I am a tank, I normally call the shots in the flashpoints since if I leave, the group will have to wait for a long time to get a replacement.
See, that is a bad attitude. I have seen Prima Donna tanks leave on their own when they are told they are doing something wrong. Which is amusing since often they are no longer required. Well geared group can complete most of the FP on their own. Some DPS will gladly tank even with an actual tank present in a group