1. EUA is the name of the system that wants to upgrade you, not the upgrade itself. It looks like the term "EUA" is being used a couple different ways. In some posts, it's the system that runs and automatically upgrades Elite customers in ranking order. In other posts, it's the upgrade inventory itself (R class through 19-Sep 2006 / F class 20-Sep onward). To be clear, it's the first one - EUA's the name of the system. So, while it's true we might hold back some upgrade inventory in advance because we're really hoping someone might still buy a First Class fare, we'll never hold back EUA from running on any upgrade-eligible flight. If you ever think that EUA didn't run on your flight (meaning there are upgrade seats available after EUA should've run), please send me a PM, and we'll definitely research it.

2. EUA doesn't run in real-time. Currently, EUA runs at specific intervals during the week before departure: nightly up to the departure day (depending on your Elite status) and one last time at 3 hours before scheduled departure. In most cases, it's well-timed with when we release the upgrade inventory, but there's always rare exceptions.

3. Upgrade inventory sometimes disappears before the nightly EUA run. EUA doesn't run right at midnight on the calendar day intervals. It actually starts running 1-2 hours before, which may explain why it looks like the upgrade inventory vanished. I'm willing to bet that when upgrade inventory vanishes instantly, it's because EUA just ran or because someone just made a significant contribution toward my profit sharing. If you ever suspect that something else happened, please send me a PM and we'll check it out.