Shows over seas and shows in the US may be different, but what I do is daily water changes and feed heavy the week before the show. By "feed heavy" I mean feed 3 to 4 times a day (or more) small meals. I know my fish will be with out food for about 10-14 days so I want as much weight on them that I can get. I feed all the way up to Saturday, then Sunday they still get the water change but no food. Starve them Sunday and hope they poop...lol. When I bag them Monday morning for priority shipping (unless they are going out express), I put 1/3 (US) cup fresh water in the bag and add the fish. If they are going out express, then I'll feed them Sunday and not Monday, ship Tuesday.
Hope that answers you question.