I forgot to lock my car one night and someone opened the door to get in but my headlights turn on when the door is opened. It was parked facing my bedroom window so it woke me up. I grabbed by DH keys and hit the horn button. Scared the daylights out of them and they ran. Come to find out they had gone up and down the whole street and broke into everyones car. Did not get anything from mine. Now I double check to make sure it is locked. PS> when I leave for any length of time all my jewelry goes with me.