No person shall, without the consent of the owner or the person in charge of a motor vehicle, change the position of the levers, switches or other parts of said motor vehicle or in any way use, occupy, injure, deface, scratch, cut, tamper with or molest any motor vehicle. Provided that this section shall not apply in case of moving or starting of a motor vehicle by police or peace officers for lawful purposes nor by members of the fire department, in case of emergency in the vicinity of a fire, nor the changing of the position of said motor vehicle temporarily without starting the motor of the same, by anyone for the purpose of extracting or removing another vehicle from a congested position. (1980 Code § 20-85)