> But they really don’t NEED walks
I think that's very breed dependent, my silkens (and the borzois before them) could easily miss a few days walks if it was too hot or I wasn't well. My collies though would be going stir crazy if they missed one walk, despite training and brain games in the house.
As to agility shows in this heat, I think you can look at it two ways. Agility dogs are generally very fit and at a perfect weight so would cope much better in the heat and the owners will be doing everything possible to keep them cool, lots of shade, water sprays, aircon in cars etc.
I travelled down to Kent a few weeks ago with my niece for the annual silken show, I didn't take my best show dog because he doesn't cope well in the heat, I did take my oldest boy though (who wasn't entered) because he doesn't mind the heat and would miss me at home, so each dog's decision was made in their best interests, I expect everyone at the agility show made similar decisions and took sufficient steps to keep the dogs happy. We also went to the racing the day after the show, all the dogs had two runs and nobody showed any signs of distress in the heat, but then sighthounds are built to lose heat.
I think it's very different a dog enthusiast taking their dog to their chosen sport, where the dogs needs come first and the owners are more aware then the average member of the public. They will be out of the shade of gazebo etc for short periods, very different to the poor (often overweight) dogs you see being dragged around town in the heat, out for hours with no shade.