Any time anybody wants to take his crypto operation out of the control of the SEC, here's all he has to do.
Take his crypto app or client, and on the send/receive pages, make a stateme4nt that the particular trade3 is a Private Membership Association trade. If the joker on the other end doesn't agree with this, then the trade doesn't go through.
Practically speaking, there would be a little more to it... like setting up a PMA statement, and making each trade a new PMA, and getting such an agreement ahead of timer from the sender/recipient.
If the Bitcoin Devs made a separate client with this stuff in it, users would be entirely outside of government oversight when they used it.