I can guarantee you that the moochers and cheaters will vanish in a heartbeat because they'll never want to provide that kind of indentification information and/or probably can not!
This is completly true! But - from a business view - maybe to hard. The goal is to get many good content. Not to prevent people from using this service. There are a lot of very good people sitting in a country where 10 dollars is a lot of money. Maybe this folks aren't familar with how to get a W-8BEN and what to do with it. On the other hand: They may insert what they want to - who will verify it?