It strikes me that the 1,500 or so members of this Discussion Board are pretty well-connected. My sense, in reading threads, is that Augusta National is probably the most exclusive, at least judging from comments of GCA DB regulars who had admitted to playing there. There doesn't appear to have been that many, compared to Cypress, Seminole, Pine Valley, and others mentioned.
(The media/volunteer point seems outside the bounds of the original question....)