I don't know the reasons for this delay. But if it was that the Ramp had a meeting, then the current/old Workchoices might have something to do with it.
In the laws it stated that if you had a stop work meeting, even for 15mins you were docked 4 hrs pay. So if you are being docked 4 hrs, you might as well stay off for 4hrs. With the morale the way it is at QF at the moment, this is probably what happened.
I don't see how this law could benefit any business, especially a business that runs to a schedule.