I was once a standby and also standing by for an upgrade. As I saw the biz seats disappear on the screen by the gate, one of the seats went to a uniformed employee. I then inquired at the podium, and the agent said there may not be an upgrade seat for me. I pointed out that she just gave a biz seat to an employee, and she actually tried to deny it. I then said something like "You upgrade employees ahead of paying passengers? I thought only United did that." I don't know if that comment helped or not, but I did get the upgrade.