I always get a sense of how I feel about the immediate world when I decide whether and how to lock my car. I live in a place where locking is not mandatory, but I also live near places where locking is probably required.
I've noticed that I even make different decisions in the same place, feeling safer - or more anonymous - at some times. For example, if I park in a big, full parking lot, I tend to assume that a thief is unlikely to select my particular car.
On a hot day I may leave a window part way open and lock up. When I do this, I feel the locks reduce temptation in all but the most hardened, rarer thief.
On a very hot day I may leave a window all the way open and lock the car. In this case I hope the lock will give me a nice, false sense of security.
As you probably suspect, nothing has ever been stolen from my car (although an entire rental car was once stolen). If I experience a robbery, I'll probably return to this post and revise everything I've said.
Comments? How do you feel about unlocked cars?