The enormous dog, as big as a Bernese Mountain Dog, turns out to be a Tibetan Mastiff puppy just like I guessed.
"Do you work at the bike shop?" Katie asks his owner, and when he confirms, Katie and he agree that the dog should be the mascot of the shop.
After we leave, I compliment her on her ability to suss out where the guy worked. "Yeah, but you guessed what kind of dog it was," she says.