I'm all for people sharing stuff privately, if that is their wish (and I'm certain it already goes on all the time via PM and other private communication). I understand that certain 'tricks of the trade', if made public on a forum such as AFF may quickly become extinct for one reason or another so have no issue if people do not wish to share them on that basis.
But I feel a little uneasy when AFF (I note the word 'community' in the URL I'm looking at) is potentially used as a vehicle for organising 'private' functions/forums (and this is not the first thread to venture close to that territory recently) which may exclude members on some sort of arbitrary basis. I might add it does not bother me if I am 'in' or 'out' in a given situation, I'm happy just to learn and share what I can via the public fora here. I doubt I have any 'tricks' that would not be widely known on AFF. But it is up to those who own and administer the site to decide what is allowable and what is not.
To the point at hand, I'm unsure how you could get say 15 or 20 people together to share their unique earning methods, without knowing prior to the occasion what they are. All 15 or 20 could potentially be the same! But good luck with the idea anyway!