I'm sure that traders ignore black swans all the time, but I was curious if you knew of, for example, a paper arguing that the majority of traders who appear to consistently get positive returns are actually exposing themselves to black swans, or a paper that tried to estimate just how common this "concentration of risk" phenomenon was.

As an aside, I wouldn't assume there existed authoritative references on a topic without having seen the references. My take: Authoritative references constitute strong evidence. Popular books, anecdotes, and short Wikipedia pages constitute middling evidence. If middling evidence implied the near-certain existence of strong evidence, then it wouldn't be middling evidence in the first place ;)