If this ever happens to me I am going to call 911 (or the equialent where I am) and tell them that I am being held hostage, which technically is true; I'm not being allowed to leave.
The airline has no right to hold you somewhere without telling you how long it will be and giving you the choice of leaving. I know this has happened in recent past with people having landed in NY being held for 12 hours after flying from Asia. I can't believe people didn't revolt and do what that FA did a while back; grab a couple of beers and pop the chute! I certainly would have.