I think the "secret fly" thing may have some association to the great lakes. I had a friend from Montana come up last fall and I had a batch of bugs tied up for him to use while he was here. He started picking through them and saying "hey, that's cool"..."I haven't seen that before..." He was looking at patterns that I would have considered "secret". On his way out he chuckled and tossed me a "secret montana fly".........a black bugger.
The most important relationship between an angler and his fly is that he has to have faith that it will get the job done. If that means believing that no one else has fished his fly than so be it...... Faith...thats the key.