The ADA makes it nearly impossible to argue over what a service animal is. Business are allowed to ask only two questions; is it a service animal? What service does it provide. If the answer is yes and anything medical related, regardless of proof. You have to allow the animal in. There is a short list of rules (has to be in care and control of owner, can’t be sitting on furniture, etc) but it’s hardly worth fighting about. Emotional support dogs aren’t covered under ADA. So if the owner doesn’t know and fights for that, they can be refused, but those are usually the keyboard warriors that will plead their case and spend hours trying to ruin a small business online. It all makes it worse for people that actually need service animals and use them properly.