What scoutmasterchip said. If thieves can, with a successful break in, steal loot, then they should lose loot with an unsuccessful breakin.
Perhaps a mechanic could be introduced that would place a dead thieves ENTIRE inventory into the secure area of a house.
If a person wants to try to break in, fine. Just know that if you fail, all of your hard earned loot/inventory is gone. And with this mechanic, a thief that choses to empty their inventory before a heist is at a significant disadvantage.
