While we are on the subject I would like to ask what is different about this campaign vs any other campaign being run on the forum?
I don't think this was a rhetorical question, although it feels like you gave the answer already:
I know everyone is gonna say 20 posts per day cap, but if those participants are posting constructive replies(yes I know a lot aren't), if they're not breaking any other forum rules, and the campaign is paying how is it any different?
I'll answer anyway: the main difference is that users can start getting paid
before having their post history checked. I think that's similar to most bounty campaigns that pay in Tokens (created out of thin air and therefore don't cost the campaign anything), but the bounty spam is more or less limited to the Altcoin boards. Yobit is all over the forum.
And that's probably why theymos banned the campaign last time, while other campaigns don't get banned.
If this campaign runs long-term, I expect many dormant accounts to wake up, make 20 posts while you're sleeping, and get paid before you wake up to ban them. The next day they'll use their next account.
My suggestion would be to stop accepting everyone (and subsequently blacklisting the spammers), and switch to the system most Bitcoin paying campaigns use: only accept people after reviewing their post history. Or as I've suggested to Yobit before: if they really insist on automated enrollment: add at least an
earned Merit requirement. That would instantly disqualify most inactive and many spamming accounts.