One of my first instructors boasted he was an airforce pilot, he was actually an assistant on a Suffolk airfield but that didn’t stop him from working for the regulator. Last I heard was from a Concorde trainer who had overheard him boasting that he flew spits…which was challenged as obviously too young. Real Walter Mitty.
As for wrong switches I only did it once and that was during an approach at night through some nasty weather when I was ordered to put the engine anti icing on, got the right switches but turned them off. Only noticed when I was ordered to turn them off so turned one on, waited to see if said engine stopped then did the second.