This remains a continual puzzle to me. (Behavior on DU.)

[tazkcmo]

54. "The airline was legally permitted to cancel his seat and offer him another."

No, they were not. They were not over booked, they were sold out.

http://www.wfaa.com/news/nation/united-airlines-now-says-flight-that-sparked-uproar-was-not-overbooked/430456020

So, the rules governing overbooked flights do not apply here. n addition, if it was overbooked, the rules clearly refer to a denial of boarding. In other words, before taking your reserved and paid for seats.

For those passengers already boarded, a different rule apples.

http://lawnewz.com/high-profile/united-cites-wrong-rule-for-illegally-de-boarding-passenger/

From the article:Rule 21, entitled “Refusal of Transport,” is very different because it clearly and expressly covers situations in which a passenger who has already boarded the plane can be removed. It states clearly: “Rule 21, Refusal of Transport, UA shall have the right to refuse to transport or shall have the RIGHT TO REMOVE FROM THE AIRCRAFT AT ANY POINT, any passenger for the following reasons.” [emphasis added]

The rule, which unlike the denied boarding rule does provide for removal “from the aircraft at any point,” lists some two dozen justifications including: unruly behavior, intoxication, inability to fit into one seat, medical problems or concerns, etc. But nowhere in the list of some two dozen reasons is there anything about over booking, the need to free up seats, the need for seats to accommodate crew members to be used on a different flight etc.

This is very important because, under accepted legal principles, a law or rule which lists in detail several different factors must be read not to include other factors which were deliberately not included or listed. So, for example, if a rule provides that a license to drive a car may be forfeited by violations of laws governing speeding, intoxication, reckless driving, or driving without a license, it cannot be read to also permit license revocation for parking violations, or for having a burned out license plate illumination light.

They had no right to forcibly remove this peaceful, law abiding, paid customer. None.