Not only that, not all the GA's are familiar with the nuances of the upgrade priority. So say they clear you as standby at the gate, you will need to ask to be put on the upgrade list (it's not automatic). I have often heard GA's tell me there are already several people on it, not understanding that Platinums will beat Golds, or something like First Class is full, not realizing there may be battlefield upgrades.

In other words, you may have to persist to get on that upgrade list.