I am surprised there wasn't some sort of covered area outside provided, or that anyone deciding to remain outside with dogs out in cages -- especially a short-nosed breed that can have problems breathing in high heat, and where heat is recognised to aggravate SM and MVD in the breed -- wouldn't have shade coverings for the crates, crate fans, etc.
I think only a vet would have been able to determine whether dogs were distressed -- having seen dogs play in the sun and end up with heat stroke -- as like kids they are not particularly able to make good decisions for themselves and of course, could make none at all if they were confined to a crate. (Are there no vet inspectors present at large dog shows?) If announcements were repeatedly made to please bring dogs inside to more appropriate and comfortable surroundings, then that suggests organisers did indeed have concerns about the welfare of dogs left in direct sun (which would be common sense for any dog owner) and indicates there were some people simply ignoring a pretty obvious welfare precaution. You;d hardly have left young children sitting in full sunlight wearing the equivalent of heavy winter coats.
But why did no one actually force people to move to a safer area for the dogs? Tannoy announcements were clearly ignored. Surely show monitors could have gone up and required people not do something as stupid as leave their dogs to roast in cages in direct sun?