I'm sure at some point in time we've all seen epic looting nightmares. More than once I've been hoping for a drop in an instance only to have another party member beat me on a need roll. Usually, though it's something they actually do need, at least as much as I do. Sometimes ninja looting is even an accident, but other times it is not.
Avirisa of Mannoroth is a might miffed that she was outrolled for a Commendation of Kael'Thas ... to a Hunter... for PvP. As a tank, she said he was running the instance to acquire that drop. Most responded that this behavior is part of what gives Hunters a bad name in the game (Huntard). Some blamed the original poster for inviting not only a Hunter, but a Night Elf Hunter to the group.