A lawyer posting on Reddit and quoted at Naked Capitalism wrote, "They did not overbook the flight; they had a fully booked flight, and not only did everyone already have a reserved confirmed seat, they were all sitting in them. The law allowing them to deny boarding in the event of an oversale does not apply. Even if it did apply, the law is unambiguously clear that airlines have to give preference to everyone with reserved confirmed seats when choosing to involuntarily deny boarding. They have to always choose the solution that will affect the least amount of reserved confirmed seats. This rule is straightforward, and United makes very clear in their own contract of carriage that employees of their own or of other carriers may be denied boarding without compensation because they do not have reserved confirmed seats. On its face, it's clear that what they did was illegal — they gave preference to their employees over people who had reserved confirmed seats..."