One of the conditions for putting the kegerator into the built in at our house was to get a couple of faucet locks. It's not so much for my kids, who have grown up around home brewed beer, but more for the friends that will come over in the future. I have two of the ones pictured (think I paid a bit less for them). They work just fine.
If I were actually worried about it, I was just remove the CO2 tank and put a rattlesnake in the kegerator.