Sometimes, deception is required for characters to make headway. If a caravan is ambushed every time there are no obvious defenders, it may be beneficial to hand the wizard a lance. Weapons, no matter how old or unserviceable maybe pressed into service for deceptive purposes. I have a house rule for this effect.
When a character is untrained with a type of weapon, but that weapon itself is unserviceable, the attacker only suffers half the normal penalty but only does half the damage. For instance, a wizard with a lance will suffer a -2 instead of a minus 4. The attacker only does 1d3 or 1d4 damage, which can be doubled for being mounted. The weapon is also dropped on impact. This modification occurs because the wielder is using a known weapon in an extraordinary way. It is not normal to fling a two-handed sword at someone’s feet or let go of a lance on impact.
Players may opt to retain the weapon, but automatically switch back to the normal -4 penalty for being untrained.
Armor can also be used in the same way, with the Armor check penalty being halved. Old, unserviceable armor is ripped away when the wearer is hit or the wearer fails a Armor check roll. Since this is really poor armor, it is easily damaged. Damaged armor still inflicts half the penalties, so characters should remove it immediately. This requires either a Dex or Str roll, at the DM’s discretion.
Another trick is Doodad Armor.
Doodad Armor is a fake armor. Typically, this deceptive armor is constructed of leather, wood and blocked felt, with metal connectors. It is very warm to wear, but far less cumbersome than real armor. It imposes one half the normal Armor check roll for the type simulated and is not destroyed when struck. However, it may show signs of distress atypical of normal armor. For example, Plate Doodad armor will show a large tear when struck by a weapon.
It functions as padded armor, no matter the type of armor simulated. This can cause an Arcane Spell Failure. Speed is unmodified by this special purpose armor, so enemies may be surprised by quick movements.
Doodad armor can also be ripped off, as it is designed to be removed quickly. This requires a Dex check.
Depending on your campaign, deceptive armor types can give a bonus one or two to grappling, as both Doodad armor and damaged armor has all kinds of extra friendly grab points to enable an attacker. The attacker would have to be aware that the armor is fake to receive a bonus. This requires either a prior strike or a Wisdom check.
One comical result is a grappler grabbing the arms of the armor and pulling, which is a Strength check. The defender can also make a strength check to rip the armor off. What happens next is usually comedy gold.