Keep them in secure show cages, use a table clothe sprayed down with pam, do not let people touch your animals unless they are buying, and keep a big bottle of hand sanitizer at your table. When you get home put ALL of the animals you took to the show into qt just like new snakes. This is what I would do. Another good thing is, the better organized the show, the healthier it will be. Most shows will even check over your reptiles to make sure that they are healthy.