Has anyone received a free upgrade on an award ticket using an Explorer Card? Is there a web page that provides details? Here are some questions: - Do you need to charge taxes to the Explorer Card to qualify? Or register interest some other way on a flight-by-flight basis? - Can you get upgraded before the flight goes to airport control, or is it only at the airport? - What are the geographic limitations? If you redeem for a business class award, can you get upgraded to first on p.s. or other 3-class North American flights? - How are you ranked in the queue - it is status first, then fare paid, and how does a saver award fare rank relative to other fares? - Has anyone gotten upgraded with the Explorer Card privilege? Details please.