You need to summon the complaint resolution officer before boarding is completed.

You must be prepared to accept any other unoccupied seat (including a flight attendant seat or aviation fan seat) on the plane.

The airline is not obligated to compensate a passenger who would have occupied more seats than he purchased and was deplaned as a result.

It is not necessary or desirable to broach the subject of whether another passenger should have purchased a second seat or a first class seat, etc. But is it OK to suggest that the airline ask for volunteers if there are no other vacant seats.

Every time someone who runs into this problem fails to follow through to his satisfaction, that makes it more difficult for the next person to do so.

>>> thread title

What might have happened if the aggrieved person himself got up and just took a different seat a short distance from the larger person before boarding was completed? I might comment that the smaller person who took the seat belonging to the larger person might have earlier given an actual reason for refusing to give the seat back -- because the smaller person's current seatmate would be encumbered.

>>> The guy in 10C isn't comfy. Let's write him a check and send the plane off with an empty seat.

In the example described, the plane would not have had an empty seat. It behooves the airline to write the check, etc. If the airline wants to give passengers a difficult time in this matter, the case belongs in court.

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