I’ve been told long ago that it’s always wise to verify periodically (like every time you return to your vehicle) that the plates on your car or truck are indeed yours. If they are ever not, notify police as soon as possible. (However don’t make the mistake of getting in somebody else’s car by mistake because it looks similar, was parked nearby, and was left unlocked.)
Or your key just happens to work.
Happened to me once. Saw "my" car (correct make, model and color), unlocked it, got in -- and noticed something about the interior was different. Checked the plate: it was somebody else's car.