just their laws. its more of a officer safety thing when making a traffic stop then anything else. when i get pulled over, im sure they're aware i have tint, i roll both windows down, turn car off, set the keys on the roof, and put my hands on the steering wheel, and at night i turn the interior lights on. never have been hassled about my tint. but its all about what area your in, how you act, car you drive, ect.
i know where madison is, you probably dont have to worry about local PD there too much with tint, but if you venture away where the state troopers patrol, if ones real bored, and you act suspicious he may come after you, other than that they shouldnt really care.
the darker the tint you go though, the more they will screw with you.