I think its better to have curtains just for the sake of the cats privacy......We have about a quarter of the cage at the front totally covered just so they can hide away if they feel threatened or frightend!
Also a cover for the roof of the cage is a good thing.....some of these show halls can be very bright and not very nice for a cat to be stuck in all day, Anything to make them feel more safer and comfortable will make them more easier to handle when ring time comes around.
Which Tica show are you thinking about attending.....BCCGB?