I do wish there was a button to turn on the rear camera while driving. Old friend of mine had the reverse switch go back on his old blazer and didn't want to pay the $80 for it to replace, so i got a manual switch hooked up. He would turn it on when people would tailgate him, some people would freak out, others wouldn't notice/care.
Actually you can turn it on by shifting trans into reverse, I have done it a few times while in neutral by accident, nothing happens because the Planetary Gears are computer controlled, no actual shifting involved. The backup camera comes on, I don't know if the backup lights come on.