I didn't see that rule stated in my OnePass Dining Program welcome letter. Anyway, my friends and I (8 altogether) went out for dinner at Il Porto, located in South Street Seaport, and the bill was for $ 240, including the tip. Since it was a participating restaurant I asked my friends, who were all paying in cash, to give me the money and I'll pay the bill w/my Amex. No problem. Got the 2400 miles later..
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Bureau of Consular Affairs:
http://travel.state.gov
Guias del Ocio:
http://www.latindex.com/ocio/guias.htm