That is wonderful! A testament to your training and his temperament. So how do you know, even when you're choosing a puppy from a good breeder, is it as simple as wysiwyg? Is the pup that seems laid-back at 7 weeks also laid-back at 2 and beyond?
I don't remember what was done during the CGC test for the reaction to distraction but I do remember in class they did some awful noisy things. A metal bedpan hitting the linoleum floor, overturning a grocery cart, throwing a heavy metal folding chair - and yes dropping a clipboard. But we had "distance" on our side - nothing hit Babykins. She didn't like the noises, and startled, but settled down. Frankly with some of those surprise noises in class I probably jumped higher than the dogs - I have a strong, uncontrolled startle reflex.For sure it wasn't that he didn't react. After all he got hit in the head, but within about two minutes he had recouped enough to get back to work. It didn't hurt at all that he adores his dumbbell.
This sort of resiliency is part of the CGC evaluation. When you get to "reaction to distractions" you wouldn't fail a dog for looking at the distraction (I drop a clipboard on the floor). What you want to see is that the dog acknowledges it and then collects itself once it realizes that it isn't the end of the world.
This class was training for AKC Canine Good Citizen and for Dog Therapy International to be a therapy dog. He wanted us, as dog handlers to know that we could be anywhere and experience odd loud noises.I find dropping a clipboard to be a reasonable level distraction and a "realistic" one since it could happen at a trial. The other things that could happen at trials include chairs and stewards tables falling over. Crashing over shopping carts sounds pretty over the top to me.