Plenty of people want to kill Good characters. All the time. They're annoying, self-righteous, and half the time or more bastards!
... Somehow your characters (or at least Duncan) don't meet any of that, so they're not targets. If you make a paladin anytime do expect that to change.
Good characters are just as guilty as Evil characters in hostile PvP, and if there's a Paladin involved its quite likely there will be a death somewhere as a result.
PvP in a relaxed non-death situation is really quite fun. Like if you're training as mercs and want to spar. Or Aessina and Leon test people in the Mage's Guild for advancement with a Mage's Duel - In which a raise scroll is placed on the floor for use as a backup, but if you kill your opponent (or yourself) you fail the exam.
PK is sometimes needed. Sometimes two characters simply can not steer clear and one must eventually kill the other. Usually a paladin is involved in this. And personally I'll complain if you kill me in an event, but don't mind PvP (which I think I've said in this thread, but don't wanna reread).
Then again, as a DM its half my job to kill all your favorite characters. (I'm quite poor at this.) Which infinitely cheapens event-related death for me.