I don't know about the U.S but here in Australia we have a points system where you lose "points" off your license whenever you are booked for traffic infringements, if you lose enough points in a given timeframe your license is suspended so it's not just the financial cost of a ticket but the fact you may lose your license that makes me keep an eye on the speedo. In all honesty though if I got caught every time I went over I would be broke, not have a license and consequently be out of a job