Another interesting tip: Make sure you are at the airport and activated about 1 hour before departure. Many times, the agents seem to upgrade off of the list 45 minutes - 30 minutes before departure. If you activated at 30 minutes before departure, you are often listed for the REMAINING seats, which typically is just "no-shows"... meanwhile, many others may have already cleared before you are added to the list.

This makes life difficult for a busy, last-minute Platinum.. who misses upgrades because he chooses to "cut it close".