California Code, Civil Code - CIV § 1710.1

Any person who, with intent to defraud, sells or disposes of a radio, piano, phonograph, sewing machine, washing machine, typewriter, adding machine, comptometer, bicycle, firearm, safe, vacuum cleaner, dictaphone, watch, watch movement, watchcase, or any other mechanical or electrical device, appliance, contrivance, material, piece of apparatus or equipment, from which the manufacturer's nameplate, serial number or any other distinguishing number or identification mark has been removed, defaced, covered, altered or destroyed, is civilly liable to the manufacturer in the sum of five hundred dollars ($500) per transaction and civilly liable to the purchaser for treble the actual damages sustained by the purchaser.

This section does not apply to those cases or instances where any of the changes or alterations enumerated in this section have been customarily made or done as an established practice in the ordinary and regular conduct of business by the original manufacturer or his duly appointed direct representative or under specific authorization from the original manufacturer.