@Quercus:
Personally, I have never seen a situation where positive reinforcement methods have put a human at risk. As with any other training method…if done incorrectly, one could fail to correct the problem they are trying to change...but there is no point in arguing the details of our methodologies.
I have seen problems with creating pushy, demanding, "entitled" animals when it is applied incorrectly. Usually when folks don't switch to intermittent rewarding, or reinforce something other than what they intended to reinforce.
I think one reason that we see more cases of people dealing with problem dogs, is that when I was kid, and probaby you too. If your dog bit a kid you did either one of three things: you told the kid "don't bother the dog anymore", or you took the vet or the shelter where it was euthanized, or you took it behind the barn and shot it.
Yes, no question about it. The usual method employed by people I knew was to discipline the kid. People usually understood the dog wasn't the party at fault. 
I teased our Sheltie until he lost his patience. "Daddy, the dog bit me!" "What did you do to the dog?" No sympathy for me! And we had that dog until he was 14 years old…....wonderful dog. I grew up and learned to respect his space.
People didn't want to understand why their dog bit, and they didn't really care, and they didn't think they could change the dog. Now people view the dog as a family member that you don't give up on, and many set up unrealistic expectations for the dog. People with problem dogs have to become instant experts, and they have people tell them they don't have a good relationship with their dog, and that they screwed up with the dog as a puppy because they were too lenient,or too harsh. When all they really want is a technique to improve their dog's behavior.
I think back then a lot of people did understand why their dog bit, if it bit. And usually took steps to improve matters. But the problem was less prevalent and I think that the way dogs were incorporated into a household had something to do with it. Dogs allowed on furniture were rare. Most dogs I knew had restrictions on where they could be in the house (ours was not allowed in carpeted areas, and he respected that whether we were home or not). And most importantly, dogs were not left alone for long periods of time. Mom was usually around, to deal with either dogs or kids or both. It makes a difference.
I am rambling…. 
Yeah, me too. As I've said before, I've been doing this a long time. When I started, the usual methods employed with dogs were positive reinforcement in the form of praise, positive punishment in the form of spanking, not so much use of negative punishment, which is more in style today, not a lot of negative reinforcement, either, although it was and is the primary method of training horses. (natural, because of the differences in what you are teaching, and the "nature of the beast") I am all for learning whatever "new" methods come down the pipe. (really, nothing is new, just "rebranded" and there is more jargon out there than there used to be) Although I have always used marker words, I find clickers great because they are more precise in use and lack the inflection of a verbal marker, which introduces inconsistency to the equation. I've employed them with horses also…...if anything, horses are quicker than dogs to offer behaviours, and they learn fast! There are many roads that lead to Rome, and the choice between them may rest with the individuals involved. One size seldom fits all, and I will not deprive myself of useful tools because they are currently out of favour. The pendulum swings, and if you live long enough you will see it swing back again......often several times. Now I really am rambling.
Merry Christmas and successful training to all.
