Whoa! How far are you from the airport and do you have status, so you don't have to wait in a long check-in line?

Why not show up, like tommorrow even, for the same flight [time] and just try something. Say, smiling, no worries, "I'm a litle early ... uh, I was wondering if you have room on the plane so I could take my flight today instead of [insert original ticket date]."

They may just want to get rid of you to avoid having to deal with you at a later date. Why? Its called delays, cancellations, etc. and, in the more than slight chance that it will happen, you would be yet another person they'd have to deal with. Right now, there's room and no problems. In fact, you would be doing them a favor by getting yourself out of the way, letting them be done with you once and for all (at least for this trip).

You'll know if the airline thinks this way by how the TA answers your question. Yes, or Yes, but I'll have to charge you (in this case, you probably didn't smile enough) or a flat No.

The best part is you can come back and post to FT what happened. You would be doing a service to us all.