could do like classic runescape style skull system. where the person who initiates the violence has a mark against him, so if the victim gets the kill instead, he wouldnt be repped down for defending himself.
it would help prevent tons of pointless killing, yet not hurt anyone who was forced to.
and people with tons of initiated kills, would be a greater reward if they were killed. so anyone who wants to push their luck on a killing spree is only drawing more people to hunt him.
to many gamemodes on blockland lack balancing like this. thats why its so frustrating and boring to play to long.