I think you may be a little on edge due to what has happened Simon, which is why you are thinking like that.
I had my sat nav stolen from the car a few years ago when I was up in Manchester. They also took a set of keys (for a house I was working at). The Police told me that they will look up the home address in the sat nav, then go and help themselves to the stuff from the house knowing that the owners are away.
In my case, they probably couldn't be bothered to make the 180 mile round trip, but it had me paranoid for months wondering if someone was going to try that set of keys in my front door.