I think the OP had more than sufficient grounds to question whether, in fact, this was a true service dog. This is the enormous disservice done by the so-called "emotional support" animals. Many, if not most, are just pets (and in my opinion, the whole category is bogus, but that's another thread). A service animal is highly trained and socialized. By definition, a service animal is "on the job," and that job includes minimizing its impact on others. A pet is a pet and, has been shown time after time, as a pet is usually not specifically trained or socialized. As I said before, my inclination would have been to ask, "Is that a service animal?" If the answer was yes, I would have taken it at face value because (1) I think service animal/human partnerships are terrific and, (2) I love dogs and wouldn't mind one (as long as it wasn't one of those little yappy ones) lying on my feet for a relatively short flight. If the answer, however, was, "Oh, it's an emotional support animal," I would have said, "Then get it the hell off my feet."

Back before "emotional support animals" I don't think this thread would even have been here.