hmm. Do some computers have accelerometers? Maybe you could do something like if you are at a coffee shop or somewhere in public when your computer is picked up before you have that turned off it does the necessary security precautions. Not sure what/if any computers have one though, but you could probably build something via arduino or something.
MacBooks used to have accelerometers that were used to detect sudden motion and park the hard disk head to prevent a head crash. But it looks like they've stopped including the accelerometers in more recent models with SSDs, since there's no equivalent need.
