I was an OBC twice--in 2003, from NY to Hong Kong (right as SARS was disappearing), and then in 2005 from Hong Kong to Tokyo.

For the first, I had to give someone documents at both NRT (during a transfer) and HKG) on the outbound. Then, I called the Hong Kong agent a day before I left. That was it. Total cost of the ticket was ~US$400.

Can't recall having to do anything for the second time.

Actually, didn't really think they were still around.