Whichever way you look at it, this has to be a spectacular own-goal for United (regardless of which partner carrier's name is in little letters beside the door).
It would have been far cheaper just to up the incentive a bit more to motivate another passenger to deplane voluntarily (or even just let the passengers sit and stew until somebody cracked), compare to the cost of the reported 2-hour delay and a ton of negative publicity.
And that's without whatever the guy gets awarded by the court ...