If so, a 2BTC charge on the 'Supporter' status means they can still technically get or create accounts, and still post nonsense and crap for the purpose of gaining higher status accounts for reselling, just without a signature campaign, obviously making less money in the process, but they should still get something on the account sale which I assume will keep them going.
I disagree that this would be case. The difference here is that when they spam, right now, they don't have to worry much about a ban because either they will:
1) Buy a new account (which does not cost a lot).
2) Create another/use another.
If there's an added cost of 2 BTC per signature, they risk a lot of money each time they try to spam. It would most likely net them a negative amount as they would be caught before they could ROI.