You can guide him to pay at once for a copper membership and get the proxyban removed as well with it.
Details here: -
https://bitcointalk.org/index.php?action=credit;promote
Details here: -
https://bitcointalk.org/index.php?action=credit;promote
Are you sure about this?
There's nothing on the proxy ban displayed message that suggests that once one pays for copper membership, the ban will be lifted.
If you paid an "evil IP" registration fee, then whatever you paid (in BTC terms) is subtracted from the upgrade fee. If you paid a registration fee a long time ago, you might even get a free Copper Membership due to the increase in BTC price. Just visit the link at the bottom of this post to check whether you have it already.
While paying for copper membership, there is a certain address in which the Bitcoin will be paid to, also the amount paid is certain specific amount.
I believe paying for coppper membership will lead to the new registered user to have copper member account account in which the evil fee is also not needed.