I think you hit the nail on the head. As expensive as it may be, you enter your judge number, category and the three scores for taste, tenderness and appearance. I am sure there are some judges out there that score the same no matter what.
I also understand that you can go from a 9 to a 5 in a box if a piece of meat is dry. But on appearance? We have seen a 3 point difference where only one judge gave a 6. They all looked at the same box. But if there is a big difference, like more than 3 points, that is where a mandatory comment card should come in play.
Someone mentioned not much variance in scores. I would guess with the popularity of BBQ comp classes this may hold true at some contest in certain regions. With all the Pellet Envy, ISS, Myron Mixon classes and others, the flavor profiles continue to drift to the same rubs, sauces, etc.