Show exposure is always scary, and a real concern, even though we don't let folks "hold" the animals.
We Black Knight our table before setup, and throughout the show, once or twice a day.
Upon returning to the shop, we soak everything- to rehydrate as well as float off any potential mite hitchhikers. Soaking won't pull off all mites, but soaking for an hour and inspecting the water will give me the confidence that there are NO tag alongs with the animals.
After the soak, we Black Knight the animals before returning to cages.
This protocol has worked very well for us for decades. BK is harder to come by, especially since I had 20 stash cases (of 12 cans a case) go POP in a fire...
For folks that let attendees be more hands on with their animals, including kids and look-e-loos, I would strongly consider a quarantine.