Headed through customs? Avoid any mention of bitcoin, they don't like it at all.
blog.glbse.com
blog.glbse.com
Consider it from the perspective of a loan - if someone you don't know well asked you for a loan, and said it was secured against "cult-booblahs" and that they were meeting with another member who traded in "cult-booblahs" this afternoon to sort it all out, it probably isn't going to go too well. From security's perspective, they are going to be immediately thinking one of: some weird drug lingo/money laundering situation, some weird pyramid scheme, or some cultist or anarchist dealing in imaginary currency. You've just made a simple question far more difficult than it needs to be.
It kind of raises the questions - why would someone with only $600 cash in the world be entering a rather expensive country for two months? From security's point of view, why would someone with only $600 cash have thrice that or more invested in some weird investment scheme? Finally, how does the founder of a bitcoin exchange have so little liquid assets/accessible emergency credit?
As an FYI, the author mentions they're from the UK or Ireland, and we were asked the same questions in both places (ensuring you have enough funds to support yourself) upon entry so this isn't US specific. Bringing enough cash to support yourself is expected (you could have said you are collecting a $10,000 loan rather than bitcoin and you probably would have still been refused - visitors should be able to demonstrate they can support themselves for their trip without relying on some deal going through once they're in the country).
I hope travel insurance covered the cost of the unfortunate trip.
As the article mentioned, he was asked about credit cards: this definitely has been my saving grace and on at least one occasion, I was asked to see how much credit I had available to me. For me, at least, it helped that I had a fairly high limit, and my latest statement to show that I wasn't close to that limit.
One other thing that works in your favour is a return flight as well as prebooked/preplanned accommodation. If you can show that you already have 'where to stay' worked out (this includes a phone number and address, especially if staying with friends), and that you have already worked out how to get home, that kind of stuff makes things a lot easier. In my experience, at least.
Factors which would not break in your favor here: you're a young man without a family, you are arriving from China rather than Ireland, you had $600 in your pocket and intend on visiting two of the most expensive cities anywhere (which are separated by a $600 plane ticket), and (probably leastly) you think you're going to get money from some shady individual in the US once you get here because of a quirky hawala system that you claim to be a participant in.
Hypothetically assuming one wants to get into the US, "Yes, I'm here for business or pleasure with a defined start and stop date. Here's the hotel reservations and itinerary. Afterwards, I'll be going back to my comfortable middle class life back home in $NATION -- you know, wife, kids, job, a whole bunch of things which are much more attractive than a sudden impulse to live in America. Money? Why yes, I have easily enough money to do what I came to do. If I needed more, I would use my credit cards."
From the point of view of the custom agent he was just an illegal worker waiting to happen.
EDIT: How can the "Founder of the Global Bitcoin Stock Exchange" end up in this situation? Doesn't inspire much confidence in this GBSE...
Also, what if you have a laptop with all your passwords and stuff, would they just go on ahead and copy your hard drive with you not being able to do anything?
Authorities tend to want to avoid that.