Everyone and their mace cans.
My dog is used to being barked at by little yippy pups at the kennel. He just learned to ignore it because when he's in working mode he knows through experience to stay on task. A little guy just won't be enough to get a rise out of him.
Now as for the owner. Not going to comment since my response is predicated on me being a 200 pound 6'1 male who is occasionally into confrontation.