Title III of the ADA gives Public Access Rights to the handler and never under any circumstances belong to the dog. As hard as it is for us dog lovers to get our minds wrapped around it - the fact is - legally per the ADA and the Dept. of Justice, a SD is considered as a piece of medical equipment.
A disabled person does not have to carry a bill of sale around for their oxygen tank, any type of license to use a motorized wheelchair, any tags on their cane stating it is government approved.
The ADA is a civil rights law not a criminal law. That is why people are not arrested for violating the ADA. Now there are some cases where someone can be arrested such as if a particular state has such a law in its criminal statutes. So in some cases the police when called can only deal with the behavior of a business employee or of a customer.
Strange that the advocates in that state kept citing the ADA instead of their State Law which is what gave the police officers the right to arrest the restaurant owner. Now under NC State Law is to be covered under their extra protection (criminal law where violators can be arrested) SDs must have a tag issued by the Dept. of Health and Human Services.
168‑4.2. May be accompanied by service animal.
(a) Every person with a disability has the right to be accompanied by a service animal trained to assist the person with his or her specific disability in any of the places listed in G.S. 168‑3, and has the right to keep the service animal on any premises the person leases, rents, or uses. The person qualifies for these rights upon the showing of a tag, issued by the Department of Health and Human Services, under G.S. 168‑4.3, stamped "NORTH CAROLINA SERVICE ANIMAL PERMANENT REGISTRATION" and stamped with a registration number, or upon a showing that the animal is being trained or has been trained as a service animal. The service animal may accompany a person in any of the places listed in G.S. 168‑3.
Federal Law (Civil Rights Law) does not require certification or tags.
NC State Law (Criminal Law) gives EXTRA protection only to those who have registered their dogs and display a tag.
So while the restaurant owner could be prosecuted under Fed. Law, the ADA, it would probably be years before the case was looked into. Under State Law, an arrest can be made on the spot and prosecuted as a criminal violation.
If someone wants to claim the extra rights given by a State they must follow the State requirements. They are not forced to follow these State requirements but by not doing so they do not received those extra benefits.