I made a policy to never sit in a better seat than a person who can make my life difficult. The list included bosses who do not understand the airline upgrading system and any clients. One time, my project team was traveling first when I realized that our client was in coach. I gave my team the option of down grading to coach or take the next flight. All three of them decided to take the next flight.
I used to be a boss long time ago, before the days of computerized upgrading. While I tried hard to travel alone, once in a while I had to be in the same plane as a co-worker. When that happens, I always try to have my companion upgraded as well.
Here is my favorite upgrade story. Only once in my life I was offered an upgrade on a transatlantic flight, Brussels to Dallas on AA. I took a gamble and refused the upgrade unless if my travel companion was also upgraded. Both of us were holding business class tickets. It worked. It was the first time he flown first over the pond. He was amazed that I would give up a first class seat for him. It is amazing how much harder people will work for little considerations. I got a lot more out of my co-workers with the upgrades than they did. I used to have great teams doing amazing projects.