Violation of city parking ordinance; affirmative defense. (1) It is an offense to be the registered owner of a motor vehicle parked in violation of a city ordinance

(2) It is an affirmative defense to a prosecution of the registered owner of a motor vehicle under subsection (1) of this section that the use of the vehicle was not authorized by the owner, either expressly or by implication. [1995 c.533 §3]