Which strengthens my point that it is bad design since it makes little sense to an average person.
The decision to use I/O or 1/0 is based on computer usage of the binary system whereby 1 = on, 0 = off.
But then, most of us aren’t computers … 
Methinks it just looked cool back in the 80’s and designers started using it on consumer products i.e. computers.
This one, IEC5009, Stand By, is ridiculously obtuse. Is it off, or is it on? What it’s supposed to represent is the crescent moon (sleep) with “on”… sleeping on? On, but asleep. On and Off?
Of course in the U.S., you might also find the crescent moon on the door of an outhouse. Resting? Dumb.
