18 Pa.C.S. § 3928: Unauthorized use of automobiles and other vehicles.

(a) Offense defined.--A person is guilty of a misdemeanor of the second degree if he operates the automobile, airplane, motorcycle, motorboat, or other motor-propelled vehicle of another without consent of the owner.

(b) Defense.--It is a defense to prosecution under this section that the actor reasonably believed that the owner would have consented to the operation had he known of it.