A negotiation with an entity that "can" (for varying definitions), and will, have you trespassed or otherwise forcibly removed is not a particularly fair "meeting of the minds". It's somewhat what happened here. Passengers _were_ negotiating. Someone offered to leave for $1500, then $1300, on video, and the gate agent responded. "Not happening. Someone's getting off or the plane's going nowhere", and look at the result.

That's "my way, or the highway", not a negotiation in any meaningful sense.

I don't know what conversation they had with him, but I'd wager a guess their policies are slanted in the direction of calling it a voluntary bump no matter what actually happens. If you don't ever actually revoke their ticket, you never actually have to pay out at 400% of the ticket value! /s

It is not the passenger's responsibility to know their rights and request the cash payout either, it is the airline's responsibility to apprise them of their full rights when the ticket is revoked for any reason. Negotiating would be offering $1600 in vouchers (or say, a value in excess of 400% ticket price) to avoid a cash payout. I would call it "negotiating in bad faith" to offer a lesser value of non-cash vouchers than the amount that the passenger is actually entitled to receive in cash, by law. (At least once you've decided, as in this case, which passenger is the passenger that is being bumped.)

I don't know what exactly "revoking the ticket" means, or if it has anything to do with a physical boarding pass, but I've heard lots of conjecture suggesting that since he was boarded and in his seat, they would not have been within their rights to revoke his ticket at all. He would have had to meet one of the "Rule 21" criteria for Refusal of Transport, in other words, those cases limited to reasons including government request, safety, failure to pay, or in cases of international travel where your documents are found to be not in order.