I. Disarm Counter?

[questionmark]

What prevents a High lvl monk w/ improved disarm from disarming a equal lvl fighter every time? Especially a dex based fighter that would not use locking guantlets(like a duelist)?

 

[Viktyr Gehrig]

The opposed attack roll.

edit: The +4 from Improved Disarm kinda negates that. But natural attacks (and unarmed strikes) are two sizes smaller than the size of the creature-- so the Fighter with a longsword or rapier has a significant bonus. With a greatsword, it's even higher.