There are studies that have proven "red" cars and all kinds of things that cause Police to pull them over, are a myth. My LEO friends laugh, and ask if anyone has any clue how many cars they see, of all colors. Said they almost always pull people over for breaking a law of some sort. They've told me that a lot of people don't understand the "Window Tinting" laws the most. It causes a ton of argument, but when your drivers window is limo blackout, it's gonna get Police attention. Would be my guess, here in Texas, they appreciate being able to see Everything.
Just put yourself in their shoes, it is 100% fact that LEO walk up on cars and get shot, randomly. It happens, if that were you, how would you know which one is time that will happen? If they see everything and there's no mystery, then there's less risk for them, thus less conflict if you're polite. I've never won an argument with Police, that's for a court (fortunately not happened for me).