It's too easy to abuse npc guards.
Someone walked up to me, said "Hi" and while I typed a response he hit me,
having both of us get killed by a guard with an assault rifle.
Then he rushed back to steal my stuff.
While I admit that it is a somewhat clever idea,
it's very annyoing and you can't really do anything about it.
Maybe only equip guards with single shot weapons to avoid this?