Re: Why have the switch ?
"It's common in the USA to wire a wall switch to a nearby socket to turn lights on and off, given that few modern houses have ceiling lights except in the kitchen."
Ah, that explains a lot. From TV, I often wondered why so many US houses seemed to have a wall switch to turn on all the standing and table lamps instead of a central room light. It probably also explains why US hotel chains bedrooms always seem so dull at night. As you stated, there's no ceiling light, just side lamps.
Biting the hand that feeds IT
