IDG Answers is a community of experts who are passionate about technology. Ask a question or answer one below.
Why not set set up your laptop to take photos of anyone who opens it, You can install Yawcam (open source, free) then review the images taken by the camera. Then you don't have to wonder who, if anyone, is messing around with it or get a useless message to your phone that alerts you that someone is screwing with your stuff but you are too far away to do anything about it. Plus you can take the image the camera captures, and set it to your wallpaper. That way, the next time the person opens your laptop, they will see their own guilty mug staring back at them, and if my skype sessions are any indication, it won't even be a flattering photo.
Another option is to install an alarm program - that will not only bring attention to someone if they mess with your laptop, it will put everyone in the area on notice that you are paranoid about your machine being messed with. Of course, if you work with someone like me, it could be an invitation to figure out how to set off your laptop alarm and freak you out whenever you turn your back on it.