Someone could probably make a fortune on car screens that you can see out of but not into. They could have pictures of people driving with seat belts on and hands on the wheel.
LMAO! and with animated images of blissful passengers mouthing the words "I love Big Bruv!"
Another wonderful idea, but sadly there's already legal precedent working against this...I'm speaking of "limotint" window tinting, which in some areas is outlawed or regulated and measured as to it's opacity i.e. effectiveness
Radiotronics, Inc. - Acek9.com Window Tint Meters
You aren't allowed to be invisible in your own personal, legally owned, expensive automobile.