The instant that he refused to deplane wasn't he in violation of failing to comply with crew member instructions (FARS)?
This will be a very interesting test case if it ever makes it to the courts, as this is the key legal issue. I'd strongly argue that no he wasn't. FARS covers crew instructions made in the interest of the safety of the aircraft and any/all of its occupants, NOT random and unreasonable instructions of any crew member unrelated to flight safety. As many of the more knowledgeable posters pointed out over and again in the past 20 pages, this was essentially a commecial dispute completely unrelated to flight safety, and arguably in breach of the CoC (as this was clearly not a case of DB). A good analogy would be if a crew member would ask you before takeoff to pay them another $500 irrespective of what you already paid, or you will be thrown off the plane. Would you need to comply ?