I think the issue is they are altering the car. If they were just scanning plates, I doubt there'd be an issue.
That was basically it, that they were 'trespassing' on private property and marking it. I searched for the case I mentioned, and it appears it happened in Michigan, not NY state.
Physically marking a tire without a warrant is a violation of the Fourth Amendment, a federal appeals court ruled. The amendment protects people from unreasonable searches and seizures.
www.npr.org
Looks like it may have been overturned at a later date...
The legal argument over the validity of tire chalking is whether the parking enforcement technique is a violation of the 4th Amendment to the US Constitution!
westwardindustries.com
"As of June 2020, on-street parking enforcement, and specifically tire-chalking, has been upheld by the courts. While there had been prior confusion or uncertainty as to the legal status of tire-chalking, the matter is now concluded, and tire-chalking has been upheld as a legal parking enforcement practice. The case that brought the tire-chalking controversy to the courts and media attention has been dismissed again and on-street parking enforcement will continue to be upheld."
Seems the argument is more a case of, "don't touch/mark my private property" which is entirely voided if the cameras and mailed tickets were used. But the court says the chalk marks represent "reasonable" search, and I'm not sure I would disagree, to be honest.