Odds 'n Ends coming off the Net:
this flight may have been one of those little connector flights and not UA per se' In the event of a lawsuit, THE UA and whoever that other company is will both be involved.
UA's CEO Munoz issued a public apology, but also mass-mailed UA employees praising them for observing proper protocol.
The "police" types who removed the passenger may have been UA employees, or from that airport's own security team. Private, not city or county cops, unless some of those do make up the local airport security team. Maybe the flight crew took it as far as they could and only then called in whoever the muscle were?
Part of Munoz' spin on this was that the 4 employees who bumped 4 customers were not going off shift or on vacation. Supposedly they were needed for another flight somewhere else, without them, that other flight would have been delayed, possible domino effect on many other flights, etc, etc.
Thinking Munoz called all his staff late last night . . . . "BE in the board room tomorrow 7am URGENT" Thinking also there will be a massive bidding war among lawyers to sign up this new free agent, who will probably turn up on one or more national tv shows before his bruises heal too much.