Just got a little jewel from American Airlines -

"Effective for tickets issued on/after 17Sep02 for travel on/after 1Oct02, changes to AA international non-refundable fares must be made and tickets reissued no later than 11:59pm on the ticketed day of departure or the ticket will have no remaining value. This will apply to all transatlantic, transpacific, Mexico, Central America, and South America non-refundable fares for travel originating in the U.S. only. This will also apply to Caribbean and Puerto Rico/USVI non-refundable fares originating in either direction...