Useful if sobering thread. I agree with those who posted noting that anything can happen until last minute and that they will allow CP cert usage even after OLCI in Economy. (I posted on my experience with this elsewhere....) The sobering part is the tale of the guy who got the last-minute upgrade and then had it pulled away from him for a ticket sale. Can't tell from the re-reading whether this should be interpreted as meaning anyone on a CP cert could/should worry that the seat will still get sold out from under them; or that anyone trying to use a CP cert "irregularly" (e.g., within T-24hrs) should have this concern; or whether this was just one of these IT timing glitches, where the Envoy upgrade got made without noting implication for other fare bucket....
I feel bad for OP that it did not work out this time. I understand the disillusion and wish that US were more aware of how all this plays out for FTers.... There have been several threads recently on value of CP status for CP certs and I go back to the following advice: If you are making CP for the CP certs, then you want to be doing it: (a) for an off-season trip somewhere, and/or because you have a lot of flexibility regarding destination or timing; or (b) because you are doing enough TATLs so that sooner or later the gods will open up a CP cert-eligible seat when you happen to be flying. Buying up, or re-arranging flying too much in hoping to use CP certs for a particular trip in the next year is, alas, a recipe for disillusionment.