Dear val ,
I just read your article with AA trouble.As an airline professional more than 30 years of experience I can reply you only about european regulation:any airline member of IATA can deny boarding to any passenger of thier choice,without explaining,but they have to pay a fee of € 200for short haul economy or 400 for long haul,plus accomodation and food and transportation to and from airport.
The second this more annoing is that they did not let you film them to avoid company and personal suing,which is illegal.My dauughter had a similar incident in2012 at milano linate airport,and the ap employee did refuse to give her his personal data,name etc,by phone I suggested my daughter to take a photo of him and witnesses as to sue this illegal act he was shouting and wantedto confiscate the camera at the cheking counter.Yet she took the photo but was denied boardigstill.She went to city center in the airline office and spoke with the manager.
She got compensation,good htl acc.and booked flight with upgtade.Tha airline is avoiding bad reputation in all cases,and airport staff usually do not work for the airline.I was director for balkans of LX Swiss International Air. Lines 2003-2008
Rastko