Now, may I point out that ALOT of people dont do this? I know many breeders that are STRICTLY against this, and many shows up here do not let the people participate. Ive never seen anyone show in 'chains'. Now as for the shank. The hands make the bit. Anyone can make a o ring harsh. I ride my QH in a longer western shank. Know why the shank is long? So you Dont have to pull and yank on the mouth. Its there for sutile movements of the hand. Ofcourse im not speaking for all the riders/trainers. Just saying that even though ALOT do this, alot Dont.
Walkers have a high headset. Saddlebreds, Arabs, and ANY horse that doesnt have the conformation is going to have a higher headset from other breeds. A horse in pain will show it in its preformance and attitude. Just because you can see the horses whites in their eyes, doesnt mean that theyre hurt. Fear, Confusion and excitement can do this.