
Fine here, but you need to remember a dog can be infectious before it shows any symptoms, so it isn't always that someone knowingly took an infectious dog to a show.
Interestingly the last time any of mine had contact with dogs that went onto have KC a few days later, none of mien got it and they were caged right next to one who was hit badly.
As I live in a city with a fairly large dog population in our walking areas mine must pick up an awful lot of herd immunity.