Hmmmm..a trick question?
Depends what you want your answer to be....Peter Bernstein, Nicholas Taleb and Karl Denninger all have their thoughts about risk...but I suppose Taleb’s might be the most significant one relative to this issue-if you believe in unanticipated risk....if you’re a cynic, and believe the biggest risk are the several elephants in the room no one wants to discuss, or deal with, why then Denninger’s your man!!
Sounds more like your “source” doesn’t understand how derivatives work.