Can he really not think of a way to show that they aren't a scam?

How can you have faith in someone that can't prove they are doing what they say they are doing? Show us what a hashtaker looks like. Release a hashtaker or a prime controller into the wild. Now that they are out of mining bitcoin and scrypt mostly and into paycoin, what could be the harm in showing us that address that they showed the wsj blog so we can see how it received freshly mined coins and sent them to the users. Put up a huge wall on one of the exchanges and prove it's you. Let one of your critics or believers pick an amount of coins and a bid price below the promised $20 per coin, show us the coins going into the exchange and show us the wall.

It really shouldn't be so hard to prove they are legitimate, but even if it is impossible, that doesn't mean there is a real reason that he shouldn't show ANY proof.