I'm a third person whose dog didn't cope with KC Good Citizen classes. A young undersocialised rescue, me flying by the seat of my pants with my first ever dog and an instructor who was (with hindsight) doing lots of things wrong. In particular there were dogs of all ages mixed in with young puppies, and one dog-reactive dog who just wasn't coping.
Mine used to manage about the first 20 minutes, then bark any time another dog got near him. I didn't realise until a long time later that he was resource guarding his "territory" (i.e. his corner of the church hall).
In the end he didn't pass his bronze Good Citizen test because he didn't like his paws being touched. What I shouldn't have done (but did) was to try it anyway; he snapped, which was really my fault. There was no support with how to help him feel more comfortable with his paws being touched, and with hindsight it was far too early anyway - 6 months in and he'd only just learned to cope with being picked up, and was only occasionally seeking physical affection from me.
The silver test has the rather bizarre requirement of the dog getting in and out of a car in an orderly manner. At that point in our lives we were living in inner London, I didn't own a car, and I doubt DDog had ever actually been in a car! What would actually have been relevant would have been having public transport as an alternative form of assessment - he was great on the tube!
Good Citizen has the inherent problem of being very goal orientated - they don't mind how you get there (in terms of training methods) so long as you get there... even when it's counterproductive overall.
It's a scheme which is fine for people who have dogs that are reasonably well balanced in the first place and need some life skills. They're the sort of dogs that might jump up at a stranger in the park if undertrained, but would be highly unlikely to deliver a serious bite, much less kill a child. It does absolutely nothing for those dogs which are starting to develop, or have already developed, significant behavioural problems.
Now, what I could support would be a system where anyone getting a dog had to undergo some training, consisting of
- before getting the dog - 4 hours of theory classes, covering things like how dogs learn, effect of diet on behaviour, positive reinforcement training, dog body language, and why a dog should never be punished for growling.
- after getting the dog - 10 weeks of dog training classes; a standard puppy class for those getting a puppy, and a more bespoke 1-2-1 class for anyone adopting a rescue dog with issues.
But while those getting puppies from semi-respectable breeders and rescue centres would find it enforced, I suspect it would be much harder to enforce for those who buy a dog on facebook / inherit their late mother's dog / get a dog from a friend who can't look after it anymore.