I like Teasel's suggestion of 'one active adult geocacher, one vote', and membership cards posted to a named individual. I don't want to publish my full name and address on the web, but I'm quite happy to let the committee have the information. Indeed, I feel that the committee should have that information - I don't like the idea of an association with anonymous voting members (even though that's effectively what we have at the moment).
Edit: changed to 'anonymous voting members'
Do not go gentle into that good night.
Rage, rage against the dying of the light. (Dylan Thomas)