As a plumber once told me, in order for him to get to the most lucrative contracts with the superstars, he was asked to join for the PFFP (Plumbers Federations of Fit Plumbers). It was his choice, and once he did, he got to work on a whole section of new housing that was being put up. Other plumbers that didnt sign didnt get a chance to be hired there. That simple.
Damn - have you ever joined a fraternity, a club, a group, an organization. Everyone has rules. We have been through this already. You can join one fraternity and then join another. Same with many places.
Hell, if you joined Bob Chick's team, who were sweating thier asses off, we werent allowed to even talk, as they were so serious in hitting that golf ball 300 yards. And Bob, it was only 340 yards, not 345. My golf cart's screen told me so!