Here is something I'm pondering...

As CO Insider has stated, "Buy-ups" are only available via online check in and "day-of" is available only at the kiosk (did I understand everything correctly?). That being the case...

At T-3 hours, they should stop the online "buy-ups" and process all the elites on the standby ug list. And then if seats remain in F, sell the "day-of" at the the kiosk. This would also cut down on the "congestion" of GAs trying to process last minute upgrades and hunting for passengers (which we've heard may at times leave people upgraded but sitting in Y = bad customer experience). This would also give the sense that the core of the FF program is being preserved.

This process then would rid me of experiencing a bad impression when at T-1 hour, all remaining seats suddenly disappear and me assuming it must be buy-ups. (Although, what do they care about my impression...off topic)

I say this since I've been watching F on my flight tomorrow (oops today).
1. I was not offered the chance to purchase up to an F fare
2. The same 5 people who were upgraded at T-4 days are the same ones on the showing on the ug list...no new people.
3. One empty seat since T-24 has been taken, no name appears on the ug list which gives me the impression that it was either purchased or bought up, nothing out of the oridInary.

Anyway...up too late...I can never sleep before a flight.