I think the vast majority of us here are informed and educated enough to control the membership, the site has grown brilliantly from strength to strength and continues to do so at a pace that suits the community.
I dont think there is a danger of over stepping the membership mark, if people read the rules and etiquette there isnt a problem, it's pretty straight forward to understand really, i just hope that the individual membership screening continues so that we can weed out any potential trouble makers or spammers. It was a problem two or so years ago, so the fact its not a problem now means the screening process is working.
I've got the same system i think on my forum, i have to individually approve each member, but i think it's worth it.
All hail mighty JD!! or something to that effect