a bunch of things going on here at once, so may as well share my thoughts, statements, questions and clarifications:
1. private club network, you only get access if your club enrolls. if your club enrolled, they likely did so to provide you with an added benefit of setup reciprocity either for free or a reduced guest fee. if the latter, it's because your club needs guest fees coming in from other places to subsidize expenses. additionally, while their clublist isnt fully public, some decent googling allows you to find it most of the clubs on it are not member-owned. theyre corporate or owned by a family entity, hence for profit.
2. as i understand it, the outpost club sets up most of its premium (top 200) access through mid-week day outings, or mondays. these events arent free to their members and i'd be surprised if a club is offering the OC a discount on its outings. beyond that, the access the OC affords isnt guaranteed. it's member to member or through their concierge. as of q4 '18, they integrated with 1000greens to facilitate much of that member to member access and to alleviate their concierge.
3. as for thousandgreens, no club can tell you who your guests can/can't be. they can just limit the # of guests you can have in a year / month or how often the same person can be your guest. (not breaking any news here). obviously, a club board can pull the "conduct unbecoming of a member" card if they don't like who your guests are or if they find out you're bringing strangers for profit. this is why TG preaches cost-neutrality and not being commercialized or monetized. its provided me great experiences both as a guest and as a host. the tiering system helps regulate things as well.
4. preserved links - from its website it says access provided "Through its members." so not quite sure why one would pay to join a group that's offering the same concept as thousandgreens, except that it's tier agnostic. i'll leave it at that.