This terrific compilation clip by [FourFour](http://fourfour.typepad.com)’s Rich Juzwiak demonstrates what a hoary cliché it has become to explain why movie characters aren’t using their cell phones.
I plead guilty, having used the “signal goes away” variation as a major element in Part Three of The Nines. (I feel both disappointment and relief to have not made the cut.)
Unlike the [air duct cliché](http://johnaugust.com/archives/2006/air-vents-are-for-air), the cell phone problem can’t be solved by a simple vow of chastity. Cell phones are real things people use every day, so ignoring them is rarely an option for a movie set present day.
Don’t write movies in which characters would call for help. That’s probably the best advice I can offer.