I remember seeing some arrogant guy on Oprah years ago bragging that he could eat the hottest of peppers without feeling the effects. Later in the show, while sitting on the couch, he accidentally rubbed his eyes. He was reduced to tears, and they had to call in medical assistance.
A gizmo like this could give kids in shop class false confidence. Fear of a spinning blade and respect for guards is what should keep fingers away from saws--not blind faith in hidden technology that might or might not be installed and working properly.
http://www.smithsonianmag.com/issues/2004/july/seat.php?page=1
http://www.1up.com/do/blogEntry?bId=4232776&publicUserId=5576180
http://www.astronautix.com/lvs/babongun.htm
http://www.answers.com/flutist&r=67
Put some corn on the ground. If he eats it, it's a rooster. If she eats it it's a hen.