Would they dare infringe on the sanctity of the airliner?

..yes, they would.

Thinking about it, I guess the lack of cell-phone usage on airliners is one of the things that I enjoy about flying. Other than the rumble of the engines, it's quiet. You can fall asleep or get engrossed in some reading without worrying that you'll miss your stop. All that becomes much harder when most of the people around you are blabbering on their cell phones. I might start having to carry some form of card around to deal with such a situation.