I live in the Upper Peninsula of Michigan -- about 1850 miles east-northeast of Bonneville, and even farther from southern California. Even though I likely will never be close enough to do regular volunteer duties at EM -- I joined one of the SCTA member clubs for a number of reasons. And since I'm not likely to do my "fair share" of duties at EM -- I do as much as I can at Bonneville (and Maxton, too) in the way of volunteering -- so that if someone were to accuse me of shirking my duties as a member of that SCTA club -- I could, with a clean conscience, point out the volunteer stuff that I do perform.
The club of which I'm a member sends me meeting minutes, a rulebook, and so on, as they do for all members. I pay a different membership fee because I'm a non-attending member (or whatever it's called). I'm happy to display the logo/sticker from the club on my support truck and race trailer.
The only drawback I've got to belonging to this particular club is the same as that comedian once said: "I'd never want to be a member of any club that would allow someone like me to be a member." But - they put up with me, so I guess I have to, as well.