I'm probably a horrible person, but I think a service animal is something that genuinely provides a service. A seeing eye dog is fine. A seizure spotting dog is fine. But I think the dog needs to be trained to perform this task - a yappy chihuahua in a handbag can't be a service dog in my opinion. If you're allowed to take your service animal to a grocery store, it needs to be working at the time, and if the dog is barking while it's working it hasn't been trained properly, and should not have been released to the person who it's supposed to be aiding. Of course, a drug or explosives sniffing dog or a police dog might be trained to bark in certain situations, but that's working too.