I would hope it is not a policy, however I have had similar situations occur with regard to upgrades. I have been at the top only to get on, and when the door close, see what appear to be non-rev moving from jump seats or other not so desierable locations up to the empty seats up front. I suppose I could complain, however I have a good string of upgrades in place and better things to complain about. Now if it becomes more common, then that's another story.