A relevant article has been posted to LawMeme, of all places: http://research.yale.edu/lawmeme/modules.php?name=News&file=article&sid=1239
If you have been following this thread here, you might be interested; the author tackles underlying issues that any PvP \'solution\' must address.

I believe that the possiblity of PK adds a useful social tension to a game. In our real society, the possibility of death and our attempts to prevent death are powerful driving forces for individual and collective activity... I think it makes sense to allow the same forces to act in a fictional world.

By permitting PK in the game on a technical level, it becomes more the responsibility of the in-game society to control PK activity (leveraging technical capabilities that are built into the game by the dev team). This would be similar to the real world, most everyone has the physical capability of killing others, but there are many other things that indirectly prevent (almost all of) us from becoming murderers on a whim or even in a flash of anger.

In my opinion, the imposition of blanket PK-prevention (even in limited territories or whatnot) would be a \'sledgehammer\' solution where something more elegant is called for. We need these indirect methods of making PKing uncommon... furthermore, I think we would find that such social control mechanics will have overall benefits for game play that are not tied solely to the PK issue.

Perhaps the existence of too much PKing is not evidence that PKing should be prohibited by a coding change, but rather is evidence that the in game penalties are not high enough!

(I learned of PlaneShift\'s existence yesterday, so I have no idea about current or planned game capabilities!)

Specific suggestions:

 - PK should be possible for all characters in all places;

 - game mechanics should permit \'outlaw tag\' that attaches to characters who perpetrate PKs. Perhaps the crime is not publicly announced (perhaps not even announced to the victim), but the tag would still be attached, so a murderer could TRY to blend into a crowd, but an observant \'public defender\' in that crowd could strike down the murderer right there without himself/herself being labelled a murderer

 - PK should be unpenalised in some cases (e.g., guild minions engaged in a declared guild war), but robustly penalised in others, with a variety of penalties;

 - Penalty: \'government\' confiscation of \'the proceeds of crime\'

 - application of a bounty on the head of outlaws (sounds like a quest to me!)

 - Penalty: permanent \'branding\' of character as \'murderer\'

 - Penalty: corporal punishment (i.e., lose ability points)

 - Penalty: house arrest, whereby outlaw tag is attached to character outside of a defined area (allows player to log in and play the character, receive visitors, but bounty hunters might be interested if the character steps outside)

 - outlaw tag can be attached globally for a fixed period of time (e,g, a week), so even at home a criminal could be hunted down (i.e., a criminal is then on the run, or can turn himself/herself in to serve a prison term)

 - Sentences might be commensurate to relative experience/skill levels of characters to prevent high-levels from picking on newbies; e.g., (a penalty) = (standard penalty) x [log(Level of PKer) - log(Level of Victim)] (or something like that, I am not a mathematician!)


Cases:

 - an assassination of a rival guild\'s political leader outside of the context of an explicitly declared guild war might be \'valid\' and \'justifiable\' in some in-game context but, like in the real world, it should have consequences / sentences for the perpetrator, if caught

 - PKer kills in an unprovoked, unwanted battle in town and so is banished from town for two weeks (i.e., now has a hard time re-supplying for two weeks, or accessing services like a bank)


Anyhow, just some thoughts!