A true RPer wants PvP everywhere. Personally I am not much of a PvPer, but being in a world where none can harm you and you are strangely invincible to other players, just doesn't make sense in terms of RP.
There could still be safe-zones and murderer penalties that would discourage griefers enough, a system that will not let anyone abuse free pvp, just to have a few outlaws running around spicing up the game for everybody else. Why does none seem to realize that? I've seen this system work flawlessly.
I hate the "we must be protected from griefers so we destroy a part of the reality of the virtual world we are in" line of thinking. It's silly at best. There are always ways to control griefing with automatic systems.