All of those instructions were so that emergency services would have an easier time cleaning up the bodies... I discovered that at the very end when they got into the paper bags the second time around and talked about the birth certificates.
Emergency services? Pardon, but I think, you´re a little naive. I don´t think, there would be any emergency services. And if there would some, what should they care about birth certificates? To make a nice tombstone for any of the millions victims?
No Emergency services. NOTHING. No one would come, no one would be alive to come. And if anyone was alive, they would be busy TRYING (if possible) to take care of the living.
I think it was a little more subtle than that. Seems like they (the bags, instructions) were a commentary about the things the government tells you to do in catastrophic emergencies. During the cold war they'd drill students to hide under their desks, etc. Remember more recently the US government instructing citizens to tape plastic bags over their windows and doors in case of a biological / dirty bomb attack? Same thing.
They're just silly things to do just to make people feel like they're doing something useful. But the government can't very well tell you: "Hey, in the case of extreme apocalyptic disaster there is nothing you can do to keep yourself safe, and chances are if you do manage to survive your very own neighbors will shoot you while you sleep, rape your wife and children, and steal all of your food. Good day!"
It may be the truth but it doesn't make them look good saying it.