Li Shenron said:I have a hard time imagining how one could sunder armor without damaging the man inside it... definitely not in combat. In a way it's a bit like trying to hit someone's dress without scratching him, which perhaps should not be impossible in a fantasy novel (Zorro?), but with a metal armor it should take at least a seriously hard effort.
I think this is the real key.
Essentially sundering worn armor is like dealing a critical to the person inside, essentially overcomplicating the system.
It is pretty much hard to imagine sundering worn armor without causing damage to the wearing and the sunder rules don't address that one.
By the way you can sunder shields.
SRD:
You can use a melee attack with a slashing or bludgeoning weapon to strike a weapon or shield that your opponent is holding. If you’re attempting to sunder a weapon or shield, follow the steps outlined here. (Attacking held objects other than weapons or shields is covered below.)