A dead man's switch for your computer? 12 years ago
To me a simple 'device proximity' check described in the article would not work if an adversary forced you to remain near the computer.
A 'vigilance control' device would work as intended in these cases - a message is issued to the user (possibly via covert means), and failure to respond locks the device:
http://en.wikipedia.org/wiki/Dead_man%27s_switch#Vigilance_c...