If he is in the U.S. he must register as a broker / dealer to operate Bitfunder, whether he allows U.S. residents to participate or not.
What I don't understand is why does he not register? The person who bites the bullet and offers the first US legal Bitcoin stock exchange stands to become billionaire rich over the next decade. People join startups and risk 5 years of their life for an opportunity such as this. Ukyo stands to gain so much if he navigated the system instead of playing games.
Anyway, once the crowdfunding law comes into effect someone will dominate this space, be that Bitfunder or someone else.
The obvious problem is none of the securities on offer are registered, so becoming a licensed exchange is sort-a pointless

Except the new law would make registering securities on kickstarter like websites far easier. I am suggesting Ukyo prepare for this change in law and take advantage of it.
If this law comes into effect, making many of our stocks legal is within reason.
The average time before bitcoin-denominated stock fails or is
shown proven to be a scam is ~ 1/2 a year.
This lends itself to, as you say, "playing games," but becomes a headache with government regulations in place.