I was responding mostly to the claim that they can only denying boarding in the event of an oversale because they can deny boarding to accommodate positioning crew, it happens all the time.
I agree that once the passenger was boarded, the situation was different. United screwed up, and they compounded the problem in their violent removal of the passenger and their subsequent public responses to the incident.
"Confirmed reserved space means space on a specific date and on a specific flight and class of service of a carrier which has been requested by a passenger, including a passenger with a “zero fare ticket,”"
"Zero fare ticket means a ticket acquired without a substantial monetary payment such as by using frequent flyer miles or vouchers" ... "A zero fare ticket does not include free or reduced rate air transportation provided to airline employees and guests".
Which means the employees cannot be counted as having confirmed reserved space. 14 CFR 250.2a says:
"In the event of an oversold flight, every carrier shall ensure that the smallest practicable number of persons holding confirmed reserved space on that flight are denied boarding involuntarily."
Which means denying the smallest practicable number of persons holding confirmed reserved space means denying 0 paying passengers. They cannot bump passengers for crew. Whether they do or not, they legally cannot.
I believe your interpretation is incorrect. This was discussed in another thread last night.[0]
Assuming 14 CFR 250 even applies (there's multiple reasons why it may not), the explicit exclusion of employees from the definition of a zero fare ticket is immaterial due to employees otherwise satisfying the definition of confirmed reserved space.[1]
The critical point is that the definition merely includes zero fare tickets, which are explicitly defined as not being employees. That does not mean employees cannot otherwise satisfy the definition of confirmed reserved space.
Deadheading employees are not involved in the operation of the aircraft, so they may be considered passengers. The employee travel passes used reserve a specific date, flight and class of service at their request.
Due to the urgency of that particular situation, the passes used were positive-space, also having higher seating priority than paying passengers. While that sucks, the alternative is that an entire flight is delayed or canceled, with many passengers on that flight missing their connections. Those missed connections then bump people off subsequent flights, creating a cascade of chaos. That's why deadheading flight crew have priority over ticketed passengers in certain situations.
[0] https://news.ycombinator.com/item?id=14095224
[1] https://www.law.cornell.edu/definitions/index.php?width=840&...