About the ponying thing, if done right, it can actually be greatly beneficial, especially on a horse that has already proven that they will buck hard or do something dangerous with a rider. Basically, you take a very broke, very strong older horse and snub the head of the green horse up close to the horn. If you know how to handle the horse you're on and know where to be to stay safe and still keep control of the greenie, then it can actually prevent a lot of problems that would have cropped up otherwise.
The biggest problem with ponying/snubbing up a green horse is that so many people have no idea how to do it properly. If done wrong, it can certainly kill everyone involved really quick.
I don't typically do it on most my greenies because I just want them listening to me from the first moment, but I wouldn't begrudge people who do want to do it that way.