I'm not so sure I agree that CO Elites pick up most of the FC seats 3 days in advance of the flight. I handle travel arrangements for 4 CO Platinums who are almost always flying on discounted/restricted tickets, and I regularly check FC availability for upgrades on itn.com. I also call the Elite line nearly every day for an upgrade for one or more of them. There have been times where there were as many as 8 available FC seats 3 days in advance, but none were available for a complimentary upgrade. It just all depends on the route. In my experience, CO does, however, open all remaining FC seats for complimentary (Elite) upgrade on the day of the flight.

Further, it is my experience that typically the flights that *sell* out of FC seats are those routes where Y is the only option when there is no Saturday stay, such as BOS-IAH, for example. So if you are going BOS-LAX via IAH, for example, it may be difficult to get a last minute upgrade, no matter what fare you paid, on the IAH-BOS upgrade, because sometimes all FC seats will go to Y-fare paying passengers that purchased their tickets 1 or more weeks in advance.

It is further my understanding that Platinum Elites are listed at the top of the standby list, ahead of non-Elite (or lesser Elite) full fare paying passengers.