Personally I can't see it working... if passengers don't want to wear their seatbelt or hide it from the CC then that's their problem; you can't blame the company if you crash but weren't wearing a seatbelt.
The lights and wiring would make the already complex wiring system even harder... it's somthing else that can break. It'll add more weight too - perhaps not a lot but we've all heard the flying peanut story.
Just my 2p.