The problem is that when they wrote the program that identified the deceased, they did not include a program to resurrect those who were incorrectly identified as deceased. The assumption was that no one would ever be declared dead that was not actually dead.
There are few, if any, human activities that can ever attain 100% perfection. It is not possible to bottle a bazillion bottles of Coke and not have at least one with an unwanted roach, cricket or other bug in it.
Even Ivory soap was only 99.44% pure. God only knows that was in that other .66%.