Only when I'm at university. Last thing I want is some panhandler coming up to my car and bugging me. At home I can leave the car unlocked for weeks at a time without worrying about anything. Hell, I could probably leave the keys in the ignition back home if I wanted to. Come to think of it, my 914 is sitting unlocked with the keys on the seat in my grandfather's unlocked barn right now. Has been all winter. Love rural areas.
ZV
EDIT: Now that I think more about it though, the 914 isn't really open to theft for a few reasons:
1) It would be a really lucky guy who got the 914 started.
2) My grandfather doesn't sleep much at night, wakes very easily, has motion lights on the barn, and keeps a loaded gun handy. He's also still an exceptional marksman.
3) My grandfather's rotwiler/german shepard mix.