I agree with Anne first off that positive training is a misnomer. And the people who mostly claim to train this way also understand that, however it's hard to come up with an alternative way to explain our belief systems about relating to dogs (some have come up with LIMA) that explains the difference between how we teach and how others teach. I don't like to call myself a "positive" trainer because I understand the falsities behind that, but until I have a better way of getting the point across I have to use a term that most people understand, and then clarify along the way.
For instance, I DO use punishment in life with my dogs, as do most "positive trainers". However the punishment I use lies only in the dog losing opportunity for a reward. Remember the definition of punishment being simply anything that occurs in a specific situation that causes the behaviour to decrease in the future. So that if the dog doesn't sit for supper, supper doesn't happen. Or if the dog doesn't sit to go outside, the walk doesn't happen. These are punishments as well. The promise I made to myself, and to my dog, however, is that I will never APPLY punishments to my dogs. This is a decision I made based not only on the science, but also on knowing the side effects punishment can bring, and lastly because I know I don't NEED it. And that's what it comes down to - from experience I have learned the it is totally un-needed in my interactions with dogs, so why would I implement something when I have other ways of fixing situations?
I also don't dole out rewards unscrupulously, in fact quite the contrary, my dogs have to work for their rewards. Whether the reward be a treat, supper, a walk, a drive, or even a head scratch at the time, they realize that doing as I ask, in turn, gives them what they want (or something similarly appealing). So this whole idea of doling out rewars left right and center is also a myth that the "other side" (yes yes, it's a JOKE!) seems to have a problem grasping as well, along with the purpose of the clicker being a marker tool, and that both that and treats are phased out over time.
To address some of your questions though - the only possible drawback to using the type of training philosophy I employ and share with my counterparts are people who use the method inappropriately, just like any other. If people ARE using treats discriminately, or not using the clicker properly, or are letting the dog do and get whatever it wants, then yes, there may be problems. However if people are consistent, have structure, and the dog understands what does and doesn't work, then they shall live in harmony.
One thing I will disagree with you a bit on, and this is simply my view (which happens to be backed by science, but we'll stick to personal views!), and that is, this ideology of "one method doesn't work for all dogs". It's very true, that some methods don't work for all dogs - the e-collar, the prong, the choke, these most certainly do not work on all dogs, even when used properly.
However, in the science of clicker training, I have yet to meet a dog, or any species for that matter in which they have a brain and spinal cord, that it does not work with. And this is not some almighty-superior phrase, but it simply is that way because it lies in the science of operant conditioning, which all animals are subject to. Within the realm of clicker training, there ARE a million and one different "ways" to teach a dog. I could make a list of probably 3 dozen way to teach loose leash walking, all different methods, but all following the same principles. And that's what it comes down to - the principles. The principles don't lie, and if you can use these principles properly, with the understanding of how they work, there is not an animal in which clicker training (or something similar, for that of deaf dogs, or animals with sound issues, like fish) will not work with. The reason it doesn't "work" for all animals lies not in the animals, but in the hands of the person trying to do the teaching.
There are objective articles out there on the use of e-collars, prongs, and chokes, you just have to look for them.Most of them lie in the scientific journals, where most science is, and unfortunately the public doesn't have access to all of those journals without having to pay for articles. But they are out there, I have five or six about shock collars here on my computer. So if you look, they are out there. [

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As for the APDT becoming "positivist" based, quite to the contrary. There are a LOT of people leaving the APDT, and others forming coalitions in which to try to get a change in some of the things that go on, because of what does go on in those groups. Because the role of the group was to educate people about dog-friendly training methods, and some of what goes on there is far from dog-friendly.
I do call a prong a prong, and a choke a choke (just as I call a Gentle Leader a Gentle Leader, not a training collar, which it is as well - there are many types of training collars, it's best to differentiate between them). I call an e-collar an e-collar or a shock collar, depending on what comes to mind. Not to try to evoke any emotional response, but for the sheer fact of that's what it does - inflict shocks to a dog. Perhaps it's not the greatest use of words, but on the other hand people who advocate these collars shouldn't be getting offended at what they are called, at least if they are going to use a shock collar they should be amenable to what they actually do to dogs. If they get their panties in a bunch over the use of shock vs e-collar terminology, perhaps they need to re-think their own priorities. [

] I know of one shock collar trainer who INSISTS that they are not shock collars, but "stimulation collars", when the fact is it's electricity, through and through. Yet she still claims she "hates" shock collars. An issue in terminology, or a problem in being okay to admit the type of training you really do? If you do it, that's fine, but at least be open to admitting it for pete's sake!
Perhaps there is a "positive-only" extremist group, in which people give in to their dogs' every whim, and the dogs have no manners, or never experience negative punishment, and the people are just doling out treats all over, but I rather think this is a pretty small group, and it's not the group you are actually hearing about when people discuss "positive" training. I certainly have yet to meet a person who believes this way, and I've been active in most of the "positive" training groups for a long time now. [

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