The same thing happened to me in Calgary last year: what we were told after 6 hours of "boarding will start in approximately 15 minutes" was that there was a se

The same thing happened to me in Calgary last year: what we were told after 6 hours of "boarding will start in approximately 15 minutes" was that there was a security breach at the airport where someone had accidentally left a door open, which required them to go through a long procedure of re-securing the affected areas and the aircraft. If that is true, however, they could have told everyone at the gate right from the start: look, we're really sorry, we screwed up and this is going to take a while. A long while. So why don't you make yourselves comfortable, go get some lunch or drinks and be back in six hours?