I’m pretty sure that the laws of any given state apply to any motor vehicle driven within that state. In Florida your windows would likely have been illegal, and with good reason. Dark tinted windows prevent police from seeing if you are armed, they prevent other drivers and pedestrians from seeing you and knowing whether or not you are aware of them, and they likely obscure your vision, at least a little. It seems to me though that with the mobility of Americans and the amount of interstate traffic, automobile regulations need to come under a federal standard.