Goodness you are dim. It never ceases to amaze me when you uphold a personal punishment/reward alignment as "more virtuous" than anything else.Complete breakdown of world communications.
7 billion people locked into place. Not a clue what is going on. Organization is on the local level. There will be communications on the local level.
People will be scared.
Atheist Utopian world.
Secular humanism is the state religion. But there is no compulsion to sacrifice for others. Evolution in the schools tells you survival of the fittest. Plus it is unlikely the authorities will be enforcing civil rights laws, and etc. Dog eat dog. Your wealth and worth is pretty much in the form of foodstuffs. Those long distance exchanges of food ain't gonna happened for a while. While the world tries to rebuild locals will resist the perfect Utopian central government. The local strongmen will do what they always have when such occurs.
Your Creator that you will have to answer to eventually commands you to love and look out for even strangers.
That's how 12 year olds think. "I should do this because it makes daddy happy."
Do you really think that the theory of evolution informs the moral thinking of the sane?