This incident may well result in a thorough, and much needed, clarification of how and when responsibility passes from ground to cockpit.
Agreed.
I find it quite interesting how all those posters who said something along the lines of 'nothing happens without my approval' or 'I'm the commander, I make the calls' have gone awfully quiet recently.
I don't think I quite fit in that category but......
If I had been the captain of that flight I would right now be feeling significant responsibility for the event and be thinking of all the different actions/communications/ management techniques I could have employed that would have resulted in a different outcome.
This could easily have happened on one of my flights as I usually defer to the expertise of both senior cabin crew and ground based personnel in situations like this. In the future I will want to quickly and quietly meet with anyone boarding the aircraft to offload a passenger to gauge their attitude/ competence/ expertise etc.