Here is the scenario: One advertisers runs a referals 2.0 campaign. His landing page is his "About Us" page. He pays publishers 43.00 USD for every sign up. To sign up, you need to use a credit card and pay money. Only, USA customers who sign up are counted. Results: Thousands of free hits without any conversions. Is G going to do anything about that?
Not sure what the issue is. If a publisher is running his CPA ads and not getting any conversions, if he has half a brain he'll stop running the ads. These things naturally sort themselves out...things that don't convert stop getting promoted.