The main problem is that it's easy to decrease PK count. You just need to use scroll that you can have in infinity amount in any location of the game. You just killed 5 ppl, clean karma and use scrolls all at same place. So you can't loose items. You don't need to decide or try to decrease PK and maybe lose items if you kill 1 more in PK and then die or stay and exp on same spot. At this position it look like infinity shots. You don't need to leave spot to buy new. But here you can PK party that came there, then just decrease PK and next time they come you will again not lose items. So feature that you drop items if you have more then 5 PK is pointless, cause no one will have so much PK.