Dicks just being dicks, mostly. Kill stealing pretty rampant back when I played Ragnarok Online.

One time I got KOd on Imagine and this guy came over. I thought, "How nice but there's no need to bother reviving! I'll just respawn to last saved point, exp loss or no." Turns out he was just came over to laugh at me. That was just one time out of many, though.