The masks can be deployed manually from the cockpit AFAIK. I wonder if they would not help with breathing in case of smoke and by fire, lack of oxygen. Fire consumes oxygen very fast, but there will be no pressure fall, so the auto system will not work. The masks fall in case of pressure fall....that's what you have to listen to before any proper flight.
Anyway, back to the topic. Romney did not look as if he was joking at all! And if that is not a bad attempt of some humor, I wonder.......