I do like the idea of a paid membership (copper) to allow users to "skip" the process of accumulating activity points to achieve a certain ranking status. If someone buys a copper membership, at the very least, it shows they have a genuine interest in participating in conversations.
I think it shows they have a genuine interest in spamming the boards to earn revenue from their sigs.
Well having a copper membership does not provide for any protection against getting banned. If you pay $40 (+ a $20 tx fee) for a copper membership, then you will need to earn at least $60 (plus the cost of spending your earnings) just to break even, so users have an incentive to not engage in activity that would result in them getting banned.
I think that is not right to give other the chance to just pay so that they will be able to use the account without worrying about the activity. It is unfair, I always think that with this forum people will learn how to push themselves to comply with rules and learn to discipline themselves. Let the rules of the forum be as it is and let the members do their best to comply with it.