In Alpha roll the dogs think there is a possibility it is going to die.......So if you do it to the wrong dog the reaction could be terrible and you could be off worse.
It can also destroy any faith the dog has in you......And so many people use it on dogs that are not to the stage where they should be dominated. Most dogs that are aggressive are actually fearful and it would make them even more so and have even less trust
An Alpha roll should really never be used by most people. The only time I feel it has some credence is when the dog is so aggressive ( not fearful at all) that it need to think that maybe it might die if it continuous to do what it is doing. I have seen it used once where it was used as a last resort, by a very experienced trainer/behaviorist, with excellent timing and strength. The dog he used it on was a very dog aggressive and people aggressive dog and it was in attack mode to another dog......this dog initially fought back and if he had not been who he was, the person doing the roll might have been injured.
She wanted to kill him too........This was a truly aggressive dog, no fear at all
No it should not be used as it is used by still so many. I hate it. By the time it comes into the picture it is too late for most dogs.
This is how many trainers feel now....of course there are still some who advocate it.
Dogs never roll other dogs to just show their strength.....the other dog rolls by choice in front of a dog who they feel is their leader. In a true dominance fight it might happen, but by then it might be fatal for the dog rolled, hence most dogs would fight back if they are of a strong personality to prevent being killed.