It appears in California service dogs are required to be registered. If the owner can't produce the dogs licence then: "Any person who knowingly and fraudulently represents himself or herself, through verbal or written notice, to be the owner or trainer of any canine licensed/qualified/identified as a guide, signal, or service dog shall be guilty of a misdemeanor punishable by imprisonment in the county jail not exceeding 6 months, by a fine not exceeding $1,000, or by both fine and imprisonment."
Would be a expensive lunch.
https://usaservicedogregistration.com/statelaws/california-service-dog-laws/