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.
I disagree.We're forgetting the main goals of our existence in this forum,we're here for bitcoins and casting our opinions on the subjects rather than investing money for ROI in terms of signature campaigns.
A better fix could be something more flexible,more efficient.Why do I see some campaigns causing less spam compared to other ? Managers ? Rules ? Fixed Posts ? Even though this seems like a complex option but could be analyzed .