I fully agree with turning it on. It would be great fun for all, and for those that say it won't be...|
Well, fine.. Add the option to be exempt from PK. You can neither be damaged nor damage. Problem is someone may find it fun to kill someone then turn PK off and be safe.
I'd say do it this way... If you want to partake in some kingdom PK, you turn it on and play around. If you kill anyone though, you are stuck with it on for 24 hours. So you can't just kill someone then go hide by turning it off. It would be great for RP. Assassination attempts, rival clan battles, rival kingdom battles and more. Must allow for more shaman huts though, or just random new NPCs in all the main areas people are (gates for example) for quick rez.