After picking a ground staff's brain for 30 minutes, here is her advice on how to significantly increase our chances of getting bumped into biz class (just in case anybody still cares).
1. Sign up for economy plus and always check in late. If EP is sold out or overbooked you will be automatically upgraded to biz. The fee is about $300 p/year. On the flight over, I sat next to a woman from Chicago who happened to have an EP membership. She mentioned that she gets bumped to biz about 25% of the time because people like myself buy EP seats at check in and they fill up fast. EP members are never downgraded to standard coach seats.
2. Dress appropriately. Passengers who are upgraded usually wear business attire and are well groomed.
3. Fly consistently with the same airline and mention that your company has a corporate account. Frankly, United service sucks, but the seats are inexpensive and upgrades are available at check-in for $200~500.
4. Be nice, a little persistant, but don't overdue it. Mention something like, "I would do almost anything for a good night sleep before tomorrow's meeting." Leave your boarding pass with the ground staff agent you personally buttered up and be patient until she calls your name prior to boarding. This gives her more time to figure things out and possibly squeeze you in.
5. Don't buy a "Y" class ticket. I was
almost upgraded to biz on the flight back to Japan, but the staff straightforward said that it is against company policy to upgrade Y tickets without paying the on site fee.