This same thing happened to me today at LAX for ATL. I did wait at the gate politely informed the GA that I was #1 on this list and there is 1 seat showing unclaimed to which her reply was "but you weren't number 1 before everyone boarded.". My point exactly! She (and a Redcoat) ended up forcing me to board. Then they came to get whomever from Y and move him to FC. I just would like a policy for ALL to follow and consistency across DL. I did send them a nice little email from 35,000 feet.
. I will post the reply from DL.