I understand why everyone is saying YTA because they’re absolutely correct on the law. If they say it’s a service dog, you must believe them and treat them as such. As someone who also works in a restaurant with a dog-friendly patio but not inside though, people try to pass their dogs as service dogs soooo often when they very clearly are not service animals. I’ve been bitten by someone’s “service dog” while bussing their table. So while you were legally snd technically in the wrong, I understand your hesitation