A recent court ruling held that police have probable cause to approach a parked car for violating a Milwaukee parking law and conduct a search .
A gun that was found in the car was admissible against the occupant who was charged with possession of a firearm by a felon. The court held the traffic violation created probable cause to approach the car, regardless of any possible ulterior motives by the officers.
The Fourth Amendment only requires that searches and seizures be reasonable – it doesn’t require them to resolve all possible exceptions before approaching a stopped car.
 U.S. vs. Johnson, 102 Crim Law 115 (7th Cir. 2017)