The idea of being buried or otherwise disposed of before one is truly dead is an old fear, which is exacerbated by the facts in this article. There is at least one funny story in here, though, to relieve what would otherwise be unrelentingly bleak. "For God's sake, Mum..." ( cracked me up )

40% of coma patients in a ‘vegetative state’ may be misdiagnosed, says a new report - Times Online

In the case of the above, there are different "reasons" why "caregivers" have given up on them. I've heard about patients in advanced stages of AIDS having the same thing done to them, but not because people thought they had died. Rather because the effort of washing/touching/lifting etc. their bodies was becoming too troublesome for a very callous someone who had total discretion, and who therefore decided to put them in a body bag before they were actually completely gone. Can you imagine the feeling ?