I remember hearing an interview with Mr. Randi where he related the story of his turning point with regard to honesty in magic. He said that as a young performer he used to do a mentalism act, and one night a gentleman approached him after the show and offered him a large sum of money to pick horses for the guy to bet on.
He went on to say the idea of exploiting the man's credulity in such a way bothered his conscience, so he told the guy it was all just a magic act, that his performances were tricks, and he did not really possess any supernatural abilities to read minds or tell the future. As I recall the story, Randi said that the guy refused to accept that answer and persisted with his entreaties, until it became obvious that the man was suffering some desperate situation. Randi said, in essence, that experience made him realize that for some people credulity is a terrible weakness, and to take advantage of that weakness would be a moral failing on his part. And that was when he made a decision to never misrepresent himself or his act ever again, and started down the road of skepticism and the exposing of liars and frauds.
I'm assuming this event must have happened some time after those newspaper interviews took place.
Now I feel it's important to point out that I'm recalling this story from an interview I heard at least a few months—and maybe even years—ago, so of course I might have gotten some of the details wrong. If I manage to look up the interview, I'll post a reference for you.
