OP here. The restaurant allows dogs, saying its illegal when it's obviously not makes no sense. He is 5 months, more than a week after the vaccination. No way was he going anywhere the day of. He goes on walks in public (touristy) areas and has met many people and dogs. He had never thrown up before so that's why it was so surprising. He has been fine since so we just have to chalk it up to excitement. He was very well behaved but very upset that none of the food going by was for him. And no we absolutely can not leave him alone while we go out. He is like a toddler, I go pee and he has gotten into something, if there is nothing to get into he chews on furniture, if there's no furniture he chews himself and barks until he gets tired. We definitely want him social and coming out with us over all that.