I know if they are in the criminal career, when they reach a certain level you can be at someones house and random click around the other sims house and the option will come up to "take something". I have not had many klepto's, so I may be wrong. I do know that the klepto will steal things from work, LOL. My sim had stuff in the family inventory and I
moused over it and it said "stole from hospital lounge", something along those lines. I found it pretty amusing.