FROM...
http://www.dot.wisconsin.gov/safety/con ... ometer.htm
Tamperers face fines and jail time
Resetting, disconnecting or altering a vehicle’s odometer to conceal the true mileage is called "odometer tampering." It is illegal for anyone to tamper with an odometer or to sell a vehicle knowing that the odometer has been tampered with.
Whether tampering is done by a backyard mechanic who resets the odometer before trading for a new car, by a person who buys a gadget to keep miles from registering on the odometer, by a dealer who contracts with a "reconditioning" firm, or by a multi-state used car mill, odometer tampering violates state and federal laws, and is punishable by fines, imprisonment or both.