It seems to me that z-8 and others have a legitimate concern with the possibility of required AMA membership, I think they put the cart before the horse. It looks much more to me like it is the government dangling the carrot of AMA monopolized RC and the AMA resisting that, knowing full well that they are and have been on a downhill slide ever since the parkflier revolution made them anachronistic unless you want to fly larger planes.
Do you think it is a coincidence that a parkflier membership carries no voting rights? Perhaps it is just an oversight. No, it is simple self-defense against the transformation of the hobby and they natural reaction of any organization to resist change. Change also means necessary change in leadership, and the present leaders are going to fight tooth and nail against that. It's only natural.
Knowing that they have a huge public relations problem inside and outside the AMA, the last thing they need is to find out what kind of whirlwind they would reap by requiring all RC fliers to join AMA! First of all, it would immediately cancel the plans to keep parkfliers in their place by denying voting rights. The feds would make short work of that. Secondly, they know that most of us would just choose to be outlaws. We'd not join and continue flying as usual. But the AMA would suffer greatly as they would be seen as making some ineffective kind of power play as RC fliers laughed.
No, the AMA has nothing to gain by any attempt to require all RC fliers to join. They have much to lose and I believe they know that. It is the federal government who is holding out the possibility. I don't know how much stronger language the AMA could use than what they already have. They want none of it.