No damage was done to the car, so I'm thinking we stupidly left the car unlocked last time we parked it.
The GPS was a cheapo refurb so it's not like we're out a lot of cash, but the sense of violation is strong. The car was parked behind our house, not on the street. It's not even in view of the street, which means someone was wandering around our back yard looking for stuff to take. I haven't checked the garage yet, hoping our bikes are still there. I didn't think of that until I got to work today.
The sense of violation is strong, and I'm not very comfortable with that.