I have 20% and have been pulled over a handful of times for other things like bulbs being out and they have never once said anything about my tint. Our laws here are 35% and when I talked to the dude who tinted my windows he said that one way for them to tell is if they hold up your ID on the inside and they can't tell what it all says they will write you a ticket. I'm not really all that sure but they've never done that to me.
I think you'll be fine unless the cop is stupid bored and needs something to mess with you with.
My name is Karyn! What's yours?
FocusXtreme - 502