At DFW I was
#1 with F1 showing on inventory. At 5 mins before boarding, nothing was cleared. I went to the counter and presented myself as
#1 on the list and asked if/when they were going to clear upgrades. The (junior) agent said, not yet, but I was virtually guaranteed the seat. I asked if they could clear BEFORE boarding so I could take the seat rather than backhauling from row 17 against incoming boarding traffic. She said to just wait at the gate then... so I watched first class and Group A board before eventually I was handed a BP. The dual line arrangement was being ignored so I had to get in the back of the line, boarding by Group C. Fortunately they did hold space in FC for a couple more bags.
I really wish they would clear F before boarding if check-ins are not 100% at that point!