Some years ago, a friend of mine, accompanied by his wife and infant child, were being held on an aircraft parked at the gate, somewhere in Asia, ie hot. There was a tech problem which was taking ages to rectify and the air-conditioning was off. He asked the crew to allow his family to go into the terminal, but was refused. He then told the Chief Purser to inform the Captain that if they were not allowed off the aircraft, he would call the British Embassy and inform them that he was being "detained against his will."
He was allowed off forthwith! (And allowed back on when the jet had been fixed.)
