I have done a no touch throw before. Only once. One of the black belt instrutors came at me and I just stepped to the side. He did ukemi then got up. I think he over committed his attack and thus lost his balance.
I have seen instructional videos showing high grade instructors doing obviously no touch or no "effort throws". In most cases the student is jumping with the techniques. But this is an instructional video showing off the style and the instructor's prowess. Hey it worked for Steven Seagal! I have also trained with instructors who do these flashy techniques but they only work on certain students attacking a certain way.
Last week on Japanese TV I saw this Nihon Kempo master do no touch throws to celebrities. He would have them stand between him and his student. Then he would push them across the floor where the student would catch them. After this he would ask the person to try and do something and they couldn't. His explanation was that he was using ki to control the person's mind, body etc. To me it looked like hypnosis. A university professor was in the studio and tried to prove this teacher as a fake which he did successfully. I wonder if anyone else has seen this kind of thing before?