You honestly think that Fishkin doesn't know his SEO? Thing is, he has to keep his reputation squeaky clean because unlike black hats he actually wants it to last beyond the next ranking update. Most black hats and their clients get caught sooner or later and then you find them bitching and moaning around the web how Google's latest ranking algorithm update is unfair and running them out of business. Guys like Rand Fishkin are smarter than that.