In practice that shouldn’t matter, as the law states that any service animal can be turned away so long as the business provides accommodation to the human (which is the point of the limited questions).
The fact this rarely happens is more due to people not actually knowing the law and typically wanting to avoid potential conflict.
"people not knowing the law" can be a symptom of bureaucracy though. How many pages of law do you think exist to open a bagel shop or add a room to your house in SFO?
It's a remark about the broader topic of bureaucracy and how you can't blame people for not knowing the nooks and crevasses of modern liberal legislature. You know, "We have to pass the bill so that you can find out what is in it.”
The fact this rarely happens is more due to people not actually knowing the law and typically wanting to avoid potential conflict.