For very large or heavy weapons, like a warhammer, wrap the haft and hilt in a long leather strap studded with lots of needle-sharp spikes. An unwrapped space near the business end lets the weapon be carried comfortably, but gives no leverage for swinging it in combat. Breaking the ties and tearing off the strap is a full-round action, in addition to actually drawing the weapon.
Somebody with no time to unwind the strap can still use the weapon, but not easily. Each time the wielder makes an attack roll he suffers a -4 penalty, and takes 1d3 damage from the spikes.
Peace-bonding a monk is tough, but in cities IMC where violent force is restricted, monks are very unwelcome. Anyone with training in weaponless combat (i.e., Improved Unarmed Strike or equivalent) must wear a scarlet headband at all times within the city limits. Folks with the headband are considered dangerous and unstable, and most citizens won't deal with them. Going without the headband, or failing to reveal ones' martial abilities at the gate, results in a mandatory sentence of mark of judgement and permanent banishment from the city.