I think Jed's provided us with an excellent object lesson as to how word of mouth stories, without critical input, can be a dangerous thing--the very point of my original post. You see, all three of these anecdotes about the success of the untrained are, in fact, false in their most common form.
1. Blue lasers were invented by a Japanese man, Shuji Nakamura, with a master's degree in electronic engineering, while working for Nichia corporation, an engineering firm. He was certainly no hobbyist.
2. The stories regarding Columbus are greatly exaggerated. The usual story goes that the scholars at the time believed the world was flat etc. The real story is that navigation of ships at the time relied on a spherical earth theory and scholars at the time believed that the journey was simply too far and that supplies wouldn't last the trip. This was almost true--Columbus greatly underestimated the length of the journey relying on wrong data, and if it weren't for the Americas in the way of his trip to Japan/China Columbus would have died at sea.
3. Proctor and Gamble archives show that the discovery of floating soap was the work of the founder's son, a chemist, not an accidental employee mishap.
So, you see, things taken at face value are indeed dangerous, especially when given with authority. Vet your sources and please don't pass on information you haven't verified yourself.