I was returning to San Francisco from Narita Airport on a Japan Airlines 747. As we were climbing towards our cruising altitude, the flight attendants were distributing pillow and blankets. The man sitting next to me was clutching his and staring at the "fasten seat belt" sign.

He was not alone. Many others were behaving the same way. Consumed with curiosity, I asked my seat-mate what was going on. Why the hugging of a blanket and a pillow while staring at the sign?

He told me I'd find out any minute.

"Find out what?" I asked.

He explained the top deck of this JAL 747 was a lounge area. Because this was an overnight flight, many passengers found it more comfortable to stretch out upstairs than remain in their more restricted assigned seats.

You just watch what happens when that sign goes off, he told me.

Within minutes, the "fasten seat belt " sign was turned off. Over a dozen men jumped up holding their bedding and raced towards the narrow staircase leading to the upper deck.