There's a huge double standard there... I see vans all the time (and pickups too) that have an air-brushed mural on the back windows, and they don't get busted! WTF? I mean, if you took out the glass in your 2 rear side windows and your hatch and filled the holes in with sheet metal, that wouldn't be illegal, despite the fact that you can't see through it! I also see all kinds of cars/trucks that have vinyl graphics all over the windows, makes it impossible to see inside, they don't get busted!
There's a way around it though. Sometimes you can get your doctor to write a prescription for really dark tinted windows (if you complain of headaches from road glare or something). In that case, you can even get your windshield fully tinted...