PVP deterent systems idea's
If you are looking for more systems for Karma, anti-pk actions, deterrant perhaps.. I don't think this was actually built for anti-pk I can't recall at the moment but it could be adapted. I can't remember if Evil alignment you would go to Underworld(hell) always or more often..etc.
This zone would also restore you to very young from old age, restore stats and skills to the appropriate levels.
The Karma Quests
Karma points are incured when you kill any lawful human, either a real player or NPC (computer operated human characters). This can happen sometimes by accident, mostly by people using area spells like icestorms, fire, nitro, javelins (lightning), etc. Since balls, javelins and wands are common, this can happen to anyone, not just wizards and other magic users."
you might view this system:
In games with open PVP and the lack of a secure targeting system, it's possible to accidentally hit / kill other players with targeted single-victim attacks, especially when a group is clustered together and the game can't reliably figure out which one you're clicking on.
Ultima Online had a solution for this in being able to drag a life bar off of any actor. Clicking this life bar was equivalent to clicking that actor, allowing for fine targeting in groups.