Yeah, I don't remember seeing any working "anti-pk" system on any of the servers I played on .
That's because they don't work. Weeelll...
One shard I was staff on many years ago had guards in the newbie city (and only the newbie city, where newbies started) which, if you committed a crime or murder or entered as a criminal or murderer, they would attempt to knock you out and if they succeeded (and they were quite strong), would teleport you into a dungeon jail where you had to use a pickaxe to mine a certain amount of stuff (which you fed to a ball & chain attached to you), before you would be teleported back to the surface world. (The penalty increased the more times you got caught, as well)
You could also be broken out of jail by players on the outside, going through the caverns leading to the jail, but there were some pretty tough monsters in the way (and this wouldn't get rid of the ball & chain, which prevented teleport spells from functioning).
For the rest of the world, anyone who was a murderer, well, it was a roleplaying shard and I don't think any crazy axe murderers ever made it through the applications process. If they did, they got banned. There were wars between different player-run empires, however, which were able to take and hold the various towns and cities, and that was fully supported.
(It also had an entirely new map. I'm a bit disappointed the shard you're all talking about doesn't. Most good shards did. It doesn't actually sound that good to me.)