I wasn't paying close attention in the period before and up to boarding. I was sitting in paid F and saw the GA come on board and start offering those on the list seats in F. The plane was only about 15% loaded so those in economy already chose to stay there.

The couple in 3E 3F were upgraded somewhere around T-24 to T-48




https://www.united.com/en/US/flights...-31/LAS/IAD/UA