Unfortunately Since1971, I don't think they're concerned whether it's seen as "fair" or not (see Sparrow for a great example of that). Probably just another thing to try and keep players playing/a gimmick. It's a shame because the rides are wonderful, and this does detract from them because it's frustrating (and to a child, I can see how upsetting it would be, especially).
Personally, I've ridden each ride 7 times. I got 3 magic pins (2 on Peter Pan and 1 on Alice). No winner so far.