Well I think a distinction should be made between griefing and banditry. There are a lot of people who kill others for survival related reason which is a legitimate way to play the game and survive, but that are also a number of individuals who just kill other players because they can and have no intention of looting them or anything and just want to ruin their day.
Not much you can do about it, but hopefully future additions to the game will help discourage, passively, this type of behavior. I suggested altering the notification that pops up in chat when a dies from "Enduin was killed" to "Enduin was Murdered near Elektro" when a person was murdered by another player. This would inform other players a PKer was in the area and other players could avoid that area or if they felt so inclined attempt to go after the bandit.
EDIT: Though in addition to that new murder notification, I dont think bandits should have a special skin, so you wont be able to know who is who exactly. And hardcore servers wouldnt feature such a notification, only normal servers.
