After parking the car in the street all day - quiet, peaceful neighborhood, directly in front of a neighbor's house - my gf came home to find the car unlocked and the cover for the locking mechanism missing.

Now - the handle is still there, undamaged, nothing taken from the car, ignition not even scratched - but the cover for where you insert the key is just missing.

I tried to find it on the ground, but by the time she told me about what had happened, it was dark and I had to give up the search until tomorrow. I was hoping to find it and see if it had been forced off or not.

My question is - can this cover pop off on it's own? And by on it's own, I mean can it pop off due to use? If so, this is a high mileage car, I can see it possibly coming loose - although I have never had this happen on another vehicle.

My next question - can I replace it? Can I buy a cover that just snaps in over it? The lock still works fine, but I want to protect the mechanism from the elements, which I can't do without this cover.

Thanks to anyone who has the answers to these weird questions.