What triggers upgrades based on status?
I recently flew from EWR-MAN and there were 5 open polaris seats 24 hrs out. At the airport two people must have used GPUs and were upgraded but they flew with 3 open seats (not occupied by guests or crew). Would UA ever upgrade people in order by status anymore or are those days long gone? To clarify I am only Silver and would not have ever received an upgrade but this flight is routinely packed with 1k and the like.