Laptop alarm system?

Do you guys have any ideas for a laptop alarm system. I feel like software based solutions are not very reliable. I am thinking of using motion sensors and rfid tags and possibly other sensors. My idea was to have an rfid reader read a nearby rfid (ideally a keychain with an rfid tag that the owner would have in their pocket) whenever the motion sensor went off. Obviously nothing would happen if the rfid corresponds to the owner, but if no rfid is detected ...something would happen (I'm not sure what would happen yet). The motion sensor can be turned off only by the owner. I'm not 100% how I would implement it but it just an idea.

Do you guys have any others? I would really appreciate your input!