I think there should be a pk system like conquer online,
You can pk everyone everwhere, but if you pk.....you get pk points, for one kill 10 points ect, then i takes 10 min. till they are gone....1 pk point in 1 min. and if you pk to much you would be go to jail and must mine till you have xxx money or something. And there should be guards at a high lvl in every town to protect pking in towns, everybody should see the person who was pket, maybe on the namecolor......till the points are gone.