As far as convincing a bunch of people. Consider that if Dan shows up to a judo competition and blows everyone away, thousands will be "believers" but how many will actually show up and train, and continue to train in that new way? Maybe 3 or 4. Well, the thing is, that those 3 or 4 people will just go seek out people like Dan themselves, so why should people like Dan bother with dealing with the millions of questions from the thousands who aren't going to be really serious about changing. Well, that's how I see it...
I don't know. I've seen a lot of guys who were 100% sure there was no value in X until they had their asses handed to them by it. For example, my judo coach came to a bjj practice once. One of the more cocky kids was sure his wrestling was far superior to judo and there would be no way that judo guy could ever teach him. He spared with my instructor and was throw very hard. He quicky tapped and no longer wanted to play. He then showed up to judo practice that saturday. Sadly, he left our club for a more MMA focused club, but I think that lesson left an impression on him about the value of judo for gi grappling.
I for one do not believe in ki projection knock outs. I think it is all fake. I personally would not waste my time finding guys like Dillman to test out my belief. However, If I saw him win a match against well respected fighter without touching him, then I would travel down there and have him knock me out. At that point I would devote my life to his art. I've always wanted to be a jedi.
Many martial arts have grown simply by traveling the world kicking peoples rear ends. That is one of the reasons why judo, bjj, and even aikido grew quickly in their early years. Had all those judoka not traveled the world fighting matches, judo would not be as popular as it is today (which is very popular everywhere but america). Had it not been for the UFC and the internet, would bjj even be a martial art in america worth mentioning?