Zange-banashi, or tales of remorse, used to be a popular genre in Japanese carnival sideshows. Notorious criminals with the gift of the gab, after serving their sentences, would make a living traveling with carnival groups telling their tales of remorse and caution, sometimes with props to lend reality to their tale. One popular figure was Matsukichi Tsumaki, the "Sekkyo Goto", or "Admonition Robber", who had been famous for breaking and entering, tying up his hapless victims, then giving tips on crime prevention advice to his (drum roll please) captive audience. This tradition petered out, as the carnivals themselves suffered the effects of an increasingly mobile population and the growing media and entertainment complex. The post-WW II collapse of censorship undoubtedly contributed to its decline, since the public could get their fix at will from any number of tabloids and weeklies, and, later, TV wide shows.
Now, by Way of a Freakonomics post comes Pros & Cons, a business that provides fraud prevention advice by ex-cons. And that elsewhere Nick Leeson is making a comfortable living managing a soccer club and, yes, telling his tales of caution.