The other week, I got a letter in the mail, with a photo taken of my license plate, stating that I had been speeding down Houston Street, at ~ 4:00am, and that I owed NYC $35.00. They don't send police after you here, they photo your license plate and send you a little love note in the mail. If you don't pay, and they catch you again, or you try to register you car, they get thier pound of flesh, or try to keep you off of the road. So be careful, the bill could be in the mail.
So, I had to return a rental car to O'hare airport during morning rush hour, and you had to pay an unexpected toll after you got off of the highway. The great State of Illinois decided not to put a change-maker (human or otherwise) at the toll station. Having been completely out of change, I couldn't come up with the 75-cents, so I stuffed a dollar in that stupid basket. I took off, bright lights flashing and cameras snapping pics -- this was months ago. Cars were piling up behind me, honking. So I did what I thought was "honest". The rental car agency hasn't contact me unlike that parking ticket I got in LA a few years back :-P
On a side note, I heard on CarTalk on NPR that a New Jersey "E-Z Pass" user moved out of state and wanted to return his pass to get his money back for the unused months. He followed the directions exactly as requested by mailing it back to the DOT. 2 weeks later he gets a bill for like $50 from the Dept. of Transportation stating his card went through a variety of checkpoints. He called customer service explaining it was impossible as he turned it in. Turns out, as the post-office truck was driving down the Interstate, it would pass E-Z pass checkpoints and bill the user! Long story short, he was refunded the bogus charges.
The absolute worst place to drive on tolls is Oklahoma City. If you get lost, expect pay like $5-10 in change to not get arrested (again, no change attendants). I have to hand it to Dallas/Fort Worth for having attendants to make change -- same with Atlanta.