Buns get QT for 30 days after the show as if they were a new bun. I usually don't get to go to more than a few shows in a season, and with four breeds I don't take the same buns all the time, they age out in between shows, it's more of a rotation. When I am finally able to do successive shows, I will probably pull out the show string and keep them separate until they are retired. I could see this getting crazy though. If I took a group,then put them in QT. Two weeks later I took another group, I would not put them in the same QT, they would need a separate, and so on...JW would be one of the breeds that would go to muliple shows.
Yes, the JW got sick last May, 5 days after the show, and that started the massive ME/ERE deaths in my barn that resulted in losing 90% of my kits. They were in QT, and I brought them in after the required time. They survived, but I lost many.