I won't deny that they do.. but i don't know of any clan that requires it. Usually you trust your clan-mates and it provides an easy way to have a good number of admins to watch out for naughty deconners and the like. Sometimes you end up with your situation, yes, but sometimes you end up on a server and there is no admin and someone screws with your base by deconning it and there is noone there that can stop Mr.X from really coming back. I guess its just up to the player to decide if the clan is trustworthy and if they want to risk scenario 2.