I personally polished my peashooter exhaust on my mk2 up for VW Festival on the outside and about 2 inches into the inside, because it looked good.. Fully aware that after a few more hundred miles it might be back to black again. So I see nothing wrong with cleaning the inside. If I do it fully once, then I can spend 2-3 minutes every time I clean the car just topping it up, so to speak.
And with regards to the shows being as you described.. You'll alyways get people that do things like chromed discs (which I'm guessing was not driven on and was swapped at the show.. Otherwise it'd wreck the finish of the chrome!

Do you not think every car scene in the world is the same though? There'll always people that want to go over the top and push the boundries to create how they want their car to look so I think leave them be.
Fair enough if you'd rather not be at a show.. It's like the people who grumble "VW Internet forums? What a waste of time, they could be using that time to work on their cars!"