If there are houses, there should be at least one chest (depending on the size of the house) that NO one but the owner can open. Of course, the amount in there would be limited, so people would only put really valuable items in there...
Then there could be other chests that are openable. Of course, the doors would be unpickable, but a group of thieves hidden can wait outside the door for the owner to open it, second he opens it rush in, kill him, and steal everything. Or just rush in and force him out. Either's good.
I remember doing that on Ultima Online once, except we made a rune and had one lookout, we all warped outside the door and killed everyone, stole their stuff, the keys, everything. Of course, it wasn't legal on the server, but we did it to people who had been acting like idiots towards our guild.
