It was reported that parking enforcement officers are no longer allowed to use chalk to mark your tires, since it was ruled that chalking is a violation of the 4th Amendment.  The 3 judge panel of the US Court of Appeals for the 6th Circuit, ruled in unanimous fashion that chalking tires is a kind of trespass.  The court found that chalking is indeed a search for purposes of the 4th Amendment, since government officials are physically trespassing upon a constitutionally protected area to obtain information.  The Supreme court ruled back in 2012 that sticking a GPS tracker to a car counted as a search, which is the same case as marking a tire with chalk to figure out how long it has been parked for.  Also they said that it was not reasonable, however if the city searches vehicles that, “are parked legally and without probable cause, or even as much as being suspected of doing something wrong, and using the touchstone of the reasonableness standard.”  That was according to court documents.