The argument made in this video is right on. It’s too easy to train the wrong thing. In a friend’s case, he simply taught his dog to chase. Two full seasons passed without a bona fide point from his dog. It found birds but just flushed them. That dog did go on to be worth its keep, but it was not till the start of its third season that the dog found and pointed a bird.
Well, there is no proof that the wing and fishing pole thing was the culprit but the owner took a certain simplistic training book verbatim and just kept at the technique with no positive result.