Basically a normal bar chair without the back rest, except it only has one leg in the center of the seat. Quite easy to balance on while awake however should one fall asleep gravity takes over and the person occupying seat is rudely and abruptly awoken by the floor.
same process for the person watching the nitration process in the nitroglycerin plant
I think the fairest thing would be an FAA opinion along the lines of "That was okay, sort of, but DON'T DO IT AGAIN!" telling everyone that in future they should divert if there is no reply from the tower for unknown reasons.
Chuks this is the FAA, we're speaking about...not likely, they'll make a big deal of it; start a million enforcement actions,and a million subsequent appeals to the NTSB, but I guess the FAA will find a 'FAR' to screw everyone involved instead of revising their own [budget driven] system; like
GF mentioned what if the tower guy had a heart attack?
...but it's never a learning process like you described wrt to FAA enforcement--NEVER!