Are most working dogs really isolated so much?
Unfortunately, yes, this is common practice. Possibly not in the boxer community, as I've not been around working boxers much, but absolutely in the GSD/Mal community.
I know of one big name "trainer" in Russia who has dogs flown into him, trains them himself, walks out into the streets and has a "stranger" (a helper) come in and beat him and the dog up (well, the helper doesn't really beat him up, but definitely beats up the dog--nice, eh?), then, he has the real owner come in and "save" the dog and nurse it back to health. Supposedly strengthens the bond. I think it's disgusting.
I've also known other GSD protection services to isolate dogs. There's a facility that trains GSD's for protection that I pass every day coming home from work that has crates set way back at the back of the property in a weedy field, which I'm positive is specifically for that purpose.
I have seen only one instance where this technique has been used that I could actually support it. I knew of a bitch that was scared out of her mind of everything and everyone. There were rumors that she may have been abused as a pup that I can't verify but she was absolutely miserable in her own skin. An individual who has been in the breed for years and years took her in and isolated her in a kennel at the back of her property, only taking meals to her. The point was that this bitch was only comfortable in isolation, and the trainer needed to work up to recreating that human bond because at one point, somehow, in the bitch's head that bond had become so twisted that she was unable to function normally. It took months, but I saw the bitch later and she was a changed dog. She was still a bit funny around other people, but she was at least comfortable in her own skin.
That said, no, I do not feel that this should be used as a part of a normal training repertoire, and as I mentioned above, it's much more widely used in other breeds than what I perceive it to be in boxers.
Ann, how old is Gus now? I have to say that we had at least one specific "episode" growing up with every one of our adolescent males where he tested the waters and tried to take the bull by the horns. Seemed like once those passed, the dog and my father had a firm understanding that the dogs never questioned again, but there were definitely the "come to Jesus" meetings between these dogs and my father. Always around 18 months of age.
My old girl, Nedra, was very much the same way--she's a very dominant dog. With her I also remember our "come to Jesus" meeting. Yes, I did need to keep on her--she was always in training--and I was *much* less lenient with her than I have been with my other two. Her temperament is much harder than the others. Had I not kept on her, I'm sure we'd been in trouble, and I know for sure that had she been in any other home the situation would have likely ended with biting (and her in either rescue or at a shelter).
I don't like describing these dogs as "drivey", rather, to me, they just have harder temperaments. A harder temperament is one that you have to stay on top of. Softer temperaments you want to stay off of. I don't know that you can say that either is exclusive to any dog's background.