Quite possibly. My cars were entered on Monday night because I forgot to shut the garage door and it took me a while to realise it had happened. And I probably would not have realised had I not heard DH leave and heard the remote door twice..

My DH took my car before I got out of bed. When I went to get in the other car, there was stuff on the seat I didn't think much if until I saw an empty pen case, then it dawned on me that the ash tray and glove box were opened.

By the time I got hold of DH, I believed i was right and we had been intruded, and he then confirmed that my door was slightly ajar and the glove box was opened.. He thought nothing of it, just that I had got sidetracked the previous evening..

So they can do subtle things. Is it a modern car? A lot of cars without advanced central locking are apparently easy to break into without obvious signs of forced entry..