i live in CA and I don't park my car in the garage. If you're like most Californians who don't have a basement/attic, you use your garage as one.

when my car is parked, it has a club on the wheel, auto-loc on the clutch, viper alarm with engine kill if it's not off, engine kill if it's cut off. Furthermore, I have my sister's Civic and the family's Astrovan parked behind me over night. They'd have to steal 2 cars to get to mine. The Astrovan is pretty loud, and you wake up when you hear it. My sister's car's pretty quiet, but her BF is trying to get her to put an exhaust and other stuff on it. If they towed it out, i think you'd hear a vehicle that is powerful enough to pull a vehicle out.