Don't know. I got waitlisted on LAX to KOA and HNL to DEN last month, but never cleared. Both flights were 100% full. I think I was 4000th in line and it seemed that everyone in 1st paid using miles. My father was on the LAX to KOA flight, is 2P, used miles and was on. I was 1P at the time and did not make it. Didn't think to check the availability before the flight. Only one person was called for an upgrade at the gate, only on one of the flights.

However, I've been waitlisted a couple times getting onto F on explus DEN-MEM and got upgraded at the gate.