MobileBeats is right. They cant write a ticket if the vehicle is registered out of state.
Ive always done 20% on the fronts, 5% on the back windows and never been messed with. I had a cop say something one time about it, but he was our high school cop and flirted with every girl in the school. My girlfriend at the time started giving him shit (in a joking way) and he quickly forgot about the tint. The biggest reason for tint laws is cops not being able to see inside when they pull you over. Ive always rolled my windows down and kept 2 hands in plain sight when I get pulled over to make them feel a little more at ease. In most states, the back windows and any extra cab windows can be as dark as you want. Its the front 2 theyre worried about. I know some tint shops will offer a deal where you pay extra up front, and if you ever get a ticket for it theyll peel it off and replace it after you get the ticket cleared. They never advertise it but some places will do it if you ask.
BTW, I grew up in MD about 20 min from Annapolis. Im not saying theyre not really strict, but Ive never been pulled over there.