Basically an npc that when you talk to, he takes away all your exp, then gives it back. So you can redo your levels again. (if you messed up the first time)
I think there should be much harsher penalties for team killing deliberately and without good reason. The only reason to team kill -ever- is if someone is looting a team member, or is a known team killer. Otherwise its just trolling and it hurts the faction.