Thanks for dropping in!

Sybil attacks are possible in real world democratic institutions. I believe it's typically referred to as "Branch Stacking" in the political sphere.

The idea here is that Moderators can validate/identify Members however they please and the ProbationTime setting prevents a Moderator from stacking his community (a sybil attack) without giving the other Mods (and Members) time to counter the attempt.

It's not perfect but this implementation would be a relatively simple way of introducing a few checks and balances.