Banksy's Identity on Ebay

Somebody is selling the real name of Banksy on Ebay. Apparently If you win this auction they "will mail you a piece of paper revealing the true identity of Banksy" on it.
How have they found out who they mysterious man is? Well, they've "uncovered his identity by matching up the prices of his sold pieces to corresponding tax records."

What's more is that currently someone is willing to pay $999,999 for a "piece of paper [that] will say his name, nothing more."

But for that hefty sum they give you "100% assurance that it is most certainly the full name of the street artist known as "Banksy"."