Yeah what you're describing is mostly ******** and the people have fallen for a play. I've seen it work on the unsuspecting, sometimes it's pressure point stuff, sometimes it's mesmerism, sometimes it's sheer belief.
There are people with real skill that is quite different out there. I recommend looking up my own teacher Lloyd Day here in Phoenix - he has a skill unlike any other I have encountered. Sometimes the lightest brush of his hand will feel as if I have been sliced to the bone. He has this uncanny ability to resist a person with a single finger. I've seen Lloyd teach people how to position their bodies to replicate some of what he does. After training with him for two years I've literally punched practice partners and sent them flying.
I have touched hands with students of Chen Zhonghua, Sam Chin, Bruce Kumar Frantzis, He Jinbao, Liu Xiaoling, Chen Xiaowang, Peter Ralston, Garrett Gee, Michio Hikitsuchi and more and it is a very different feeling from each of these styles but these have more in common than they would in sensation than say a standard wing chun player, kickboxer, or a good BJJ guy. There's this torsional screw power that can be expressed only with enough relaxation and training. Certain external alignments as well as coordinations of the limbs create sensations that once you pay attention to them you can reproduce outside of the forms in fights. It can be manifested in so many ways dependent on the intent behind what is done to an opponent. Truly amazing work at times but it is a long process to bring it to fruition to be used in a fight.