I bowed out of this thread early because I realized that my experiences were mine, and thus clear and convincing to me. I didn't think I was gonna persuade anyone who had formed an opinion...
But after briefly dipping back in to read the posts of people I respect I have decided to add this:
The almost all best dogs I have ever known absolutely LIVE to chew on people. They see it as a game with a chew toy at the end until they get a few street bites. I can think of a couple GSDs, a couple of Dutchies, and a couple of Mals. Including the one that has played with my kids the last 7.5 years, currently laying at my feet chewing rawhide. I know what collar wise is, and it is something I took precautions to avoid suggested by several "name" trainers, but he is smart enough that he was able to piece it together...
The E-collar turns suggestions like "go lay down" into commands (DOWN!) The tracking harness tells him "let's go find someone to fuck up". The agitation collar (he was choking himself when using the harness for bitework; a correct agitation collar fixed it. I am still shaking my head at that) tells him "oh, goody, I get to fuck someone up". Fur saver or prong collar on a leash suggests to him "aww,hell, I better do good or I might not get to fuck someone up..." My dog frequently wears several collars at a time, depending on what we are doing. The most frequent are the E'collar, the prong collar, amd the fur saver in that order. Oh, and he always has a flat collar with the sole purpose of carrying ID/Vax tags.
Dogs see things pretty black and white, with the oft quoted intelligence level of a 2-5 year old child. My dog, despite escaping the yard several times has NEVER bit someone I didn't want him to. But he is a dog, and I have to be vigilant as though I had a gun that could walk around and do things of its own volition....and do everything I can to control its limited decision making abilities.
pat