This CP posted an update on Flyertalk: He wrote a complaint letter to Customer Relations. They replied with the typical spin about the Choice Seats program being a benefit to elites...........and gave him a $50 ETUV for the inconvenience. He said that had they just given him the aisle seat when they re-booked him, he would not have had any reason to complain.
Now US is going to have to sell 10 Choice Seats to make up for one instance of not bending a rule which makes no sense in the first place........and the customer is still angry.