An article in The Australian details how increasingly, deceased Irish people are taking their cell phones with them to the grave.

http://www.theaustralian.news.com.au/common/story_page/0,5744,17175640%255E29677,00.html

In Victorian times, some people were so terrified that they would be buried alive, they were sometimes interred with a string around their finger, which extended through the coffin, up through the soil, and connected to a bell above the grave. Watchmen were employed to listen for the sounds of the bells in graveyards, signifying that a recently arrived resident was not quite dead yet.

Perhaps this is the modern equivalent. But which carriers could ever guarantee that one could get a signal through a casket and six feet of soil?

TES