That is only enforced if you register your dog with the city. It’s required by law to register your pet and pay a yearly fee, plus show vaccination records. But it is only enforced if the police stop you for some reason while you are with your dog and they happen to ask about your dog’s registration. If you only walk you dog on leash and never take it anywhere that a cop might talk to you, nobody would ever know your dog wasn’t registered. If you never take your dog to daycare while you are on vacation, nobody would ever know your dog didn’t have vaccinations.