Originally Posted by cAAribmorpho

When you check-in, do you check the "Add me to Airport Upgrade List" (that's probably not the exact name, but something to that effect)? You won't be on the waiting list if you don't do that.

A little earlier this year I forgot to do that on a packed LAX-DFW flight. I looked at the screen, didn't see my name (even though I had requested the upgrade at booking), asked the GA about it, the agent did some quick typing and I appeared at #2 on the list (and got the second-to-last seat, I believe, in F).