Sustainable community - Sign me up?

What could possibly be wrong with a planned sustainable community?  Why not form one with like-minded people?  Well, this one is just perfect for the right kind of gun-loving paranoid conspiracy theorist apocalyptic survivalist greenie, if those aren't contradictions in terms.  This might work OK if they could be locked in, or tricked into a siege mentality so they locked themselves in.  When you build it to look like a medieval strong hold, or prison, this might not be too difficult.