I would not rely on people reading that text... But usually the physical world gives you a bit more feedback on the actual state the switch controls. If the ele

I would not rely on people reading that text... But usually the physical world gives you a bit more feedback on the actual state the switch controls. If the electricity just went out and you go to the fusebox and find a row of breakers where one is pointing the other way and says off, it's pretty obvious what it does - and you get immediate feedback when you flip it.