I think we need to keep in mind, though, that not everyone puts as much of their life into their dogs as we do. Some of them do not have the time, or the interest, in learning about learning theory, about "best" training methods...they just want a dog to be safe, to be happy, and to have a little bit of freedom. And I can't tell them they are wrong for that.
Frankly, my guys are trained (pretty simply, too) that they have the entire backyard to run free in, but that they cannot run past the tree line on the back yard property line or the two sides, and they cannot pass by the first wall of the house to the front yard. I have no fence, I rent so am not allowed one ....now, I was determined to not use an efence, so I worked at it. And I succeeded. But...I also know most people don't have the time, knowledge, or energy to do such work - as it starts with foundation stuff, not just a simple recall or boundary training.
I do not recommend efences. I will try to educate people into other ways of containing their animals, if they ask. There are obvious possible downfalls for efences. However, you are really just blowing smoke if you try to convince people who have used it, and have no problems with it, that they are inherently wrong. Clearly they've done something right with their dog. Maybe someday they'll have a dog that will have a very bad reaction and they will understand or rethink a situation. But, maybe they never will. You can never know. And to be honest, I don't think the rates of defective ecollars are nearly as high as it is being assumed here. I don't say that from any sort of support for ecollars, but from a mere marketing standpoint. Collars that injure, misfire, or don't work properly don't sell. Period. Yes, sometimes you'll get one, but it's probably actually quite rare.
I do not use them. I do not recommend them. I acknowledge that there are some inherent risks in using ecollars (the training or the fence kind) with certain kinds of dogs. There is a very high risk of misuse by the handler. I've seen some pretty serious outcomes of ecollar use - from prongs imbedded in the neck, to serious DA because the collar was used to teach the dog to ignore other dogs, to shut-down dogs, to all sorts of problems. I am honest when I say that I have ethical dilemmas with the use of electricity in training, that while I try hard to not let affect my judgements, I also realize our values are what they are. I live in an area with a very high ecollar use, and because of my experiences I will educate about other ways to train. Because of these risks, I do not think they should be sold on pet store shelves. I think you should be forced to learn from somebody who uses learning theory and has background in it and how to apply the stim with proper timing and efficacy - you shouldn't be able to pick one up and slap it on your dog.
But I would be lying to myself if I said that all dogs had bad reactions or would turn out that way. I do see a lot of dogs who have no obvious problems from the use of the ecollar. That doesn't mean I support their use any more, it just means I'm honest when it comes to what I see.
And while I know the risks, and I know why I teach other ways, again you can't argue with folks who use them with no problems, so there's no point in trying. If anything, I will listen to them, and listen to what made it successful for them, because that is as important as anything. You might ask why I think that is important? Because someday I may encounter a situation in which a person is devoted to using an efence, for whatever reason, and will not change their mind, and if they ask I can at least give them some safety measures to follow of "what worked for others" as well as "what didn't and what may go wrong". I can give a complete picture. Somebody may or may not jump on me and say "doesn't that mean you are supporting efences???". And I will say no, it does not, but I have to think of the needs of the dog, and what will best keep this dog both mentally happy and safe despite its situation. If giving a few pointers of what worked for someone else keeps that dog in its home or keeps a child from finding their dog dead on the highway, then I'll listen to those who do use it and try to glean a bit of useful information from them. Because I would feel awfully high and mighty if I just made the owner feel bad for using the fence (as happens a lot), didn't provide any useful information, and the dog ended up dying because that person had the guts in the first place to come to me for help and I failed to do so within that person's needs. Clearly they wanted to do the right thing, or they wouldn't have looked for help in the beginning.
Then again...I'm not in any camp. My tent is located all by itself on a little secluded island. I never was much of a follower.