I think people have been sufficiently trained in using off buttons that if you give it the right affordances (visibility, an On/Off label, an LED to show it's o

I think people have been sufficiently trained in using off buttons that if you give it the right affordances (visibility, an On/Off label, an LED to show it's on), they'll be able to use it without too much friction. After all, they had to turn on the computer first.