A lot of the sentiment behind your post-course lecture should actually be enforced through an increased oversight and supervision of flying by clubs. I know it can be difficult to enforce once someone gets out away from their flying school and buys into an aircraft but it is a worry. The club I instruct for at the moment has a minimum number of hours P1 before a pilot can self-authorise a flight otherwise they have to get an instructor or authorising pilot to authorise the flight. Even self authorising pilots are encouraged to let an instructor know where they're going. It may seem a little OTT but most pilots seem to work with the system. If I were in WWW's shoes with Mr. Overconfident I'd be happier letting him fly in that environment.
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Get there eventually