Except it wasn't used in that manner at all. As others pointed out, it's a fricken idiom and automatic response in a photographic context. http://goo.gl/CnV1s
It's the same as if he replied 'okay, don't worry, the photos will be dead and gone', and the flight attendant misinterprets that to mean he's going to blow up the plane and kill everyone.
If the story is as he's relayed it, he's absolutely 100% not at fault and the flight attendant is a total fricken idiot.