Yeah, as I kept watching, it became clear that the guy was a spectator who like to carry a heavy bag of discs around. Though, I also thought spectators were not supposed to be allow to hang out with the player group.
Pretty sure that's up to the event. How stringent they are in separating the players from the gallery depends on their prerogatives. When there's 10 people following the card, it's a little less important to make a distinction and keep them separate, compared to a couple hundred lining the fairway.
I also got the impression that the times where the players were interacting with the crowd and petting the dog were when there were back-ups, and the players were giving the teeing group space by staying back with the spectators.