It's just like any other organization....they can set their rules, you can choose to join or not....
examples.
Yacht Club -
http://www.dlyc.com/rules.html
Tennis Club -
http://www.iiasa.ac.at/~marek/tennis/Docs/rules_e.html
Golf -
http://www.goldcreek.com/golfrules.htm
Same thing imho. Choice is up to the consumer.