https://www.techdirt.com/articles/20210828/18314947457/sixth-circuit-reaffirms-fourth-amendment-violation-to-chalk-car-tires-parking-enforcement-purposes.shtml

Two years ago, the Sixth Circuit Court of Appeals surprised the city of Saginaw, Michigan by finding the process of marking car tires with chalk for parking enforcement violated the Fourth Amendment. The city certainly didn't expect multiple ticketholder Alison Taylor's lawsuit to make it this far. And it certainly didn't expect the Appeals Court to reverse the district court's decision that no Fourth Amendment violation had taken place.

Contrary to expectations, the Appeals Court ruled in 2019 that chalking tires certainly appeared to violate the Fourth Amendment. And the city was unable to successfully argue otherwise. Relying on the Supreme Court's Jones decision, the Appeals Court said the city unreasonably "trespassed" on the private property of residents (that being their cars) to apply the chalk mark -- property still protected by the Fourth Amendment against unreasonable searches despite being parked on public streets.