Make this a dead man's switch?

[Gaff]

Could this be changed to act as a dead man's switch so that the computer halts if a USB device is removed?

[KevinKrause]

This is already built in as per the help message:

usbkill is a simple program with one goal: quickly shutdown the computer when a USB is inserted or removed.

[amelia-bartlett]

What about making it so the usb device has to be occasionally unplugged and replugged - say every day/week or time interval of your preference?