Thinking about all the "INAL" answers and the obviously wrong "legal" advice and opinion on legal topics you can come across on HN on a daily basis, I think law is good example of people overestimating their knowledge.
Replace figure skating with any other sports, so, and try having discussions about, e.g, a defeat of any soccer team. All of a sudden everyone just became a soccer coach. And everyone is able to critique individual player's performance and skill and technique. If anything, this proofs the DK effect rather well.