My dear departed mother had a morbid terror of being cremated alive. It was such a concern to her, that she made me promise to stick a pin in her on her deathbed to check that she didn't flinch. I tried to persuade her that since she would be laid out for several days, there was every likelihood that a passing undertaker would notice her tapping out S.O.S. in morse with her finger but she would have none of it. So yes, I pricked her finger.
She is in good company. George Washington no less, was so terrified of the idea of being buried alive that he made his servants promise to wait for 2 days after his death before burying him.
Fear of being buried alive, the medical term for which is 'Taphephobia', was so common in the 18th and 19th centuries that the 'safety coffin' was invented. This was a coffin with a cord inside attached to a bell above ground so that anyone who might awaken to find themselves in a small, dark, confined space could feel around for the rope and set the bell ringing. It seems to have escaped people's attention, that a bell ringing from a churchyard is a fairly commonplace event.
Of course, this fear of premature burial is completely irrational especially nowadays with modern medicine being so advanced. By the way, while I think of it, when it comes to my turn, I'd be obliged if I could be buried with my mobile phone - only because I am so fond of it. Oh, and if you could just make sure that it is charged up I'd be most obliged.