If someone pulls extra on accident then you help them. Its happened to us all so no big deal. If they do it on purpose then either they're doing it with threat redirection or they're telling me they can handle it and I ignore them. Player power today is so high that if you wanted to you could (and I have with several classes) solo to level cap soloing at level dungeons and raids. If they can't handle an extra mob or two that sucks for them but I'm busy and want to be done asap so I can move onto the next one. I assume we all value or time and I'm not wasting it saving lemmings.