No person shall leave a motor vehicle, except a commercial motor vehicle, in a business or industrial district, unattended on any street, alley, used car lot or unattended parking lot in the City without first stopping the engine, locking the ignition, removing the key and taking it with them; provided, that any violation of these provisions shall not mitigate the offense of stealing such motor vehicle nor shall such violation be used to effect a recovery in any civil action for the theft of such motor vehicle or the insurance thereon or have any other bearing on any civil action.