Here in Florida, virtually every car has tinted windows, and I would guess well over 50% are tinted illegally dark.
When I bought a new car several years ago, I went to one of the big tint shops and they gave me the options. The first thing the guy said was do you "need the legal ones" or the "standard" ones.
I didn't go totally dark, but still much beyond what is technically legal. But then, the only cars on the street that appear to be legal are likely rental cars. About one out of ten cars here is so dark that you cannot possibly see anything inside.
Police don't give a rat's behind here about tinted windows. Virtually every police car you see here has illegally tinted windows.
Remember, we have a lot of sun here ... the Sunshine State.
Rub a Dub