I don't think the spectator should have to pay, but WE as the exhibitors should get discounts and be treated like the owners of the busness or persons putting on the cruise/show appreciate us coming there with our cars.
Does the audience pay to see Aerosmith, or does Aerosmith have to pay for the opportunity to play to the audience? You pay to go to a ball game, or do the players have to pay to play??
Really no different, we have just come to accept the status quo.