It already did happen: I've used keyboards with shutdown and reboot keys, and yes, it's a terrible idea.

My alma mater used to run programming competitions in a lab where the workstations had the reset button exactly at knee height. This wasn't a problem normally, when you're sitting under the desk next to the computer; but when you have three or four people gathered around the screen, kicking the reset button was a definite possibility. Eventually taping the cover of a calculator over this button became part of our regular routine.