I only saw the last few minutes. The show is all about kids setting up and managing one another without supervision from adults. In other words, if kids ruled the world, how would it turn out?
At the end of every week, they have a host, an adult, that asks every kid if they want to go home. This past week an 8 year old boy decided he missed his family too much and chose to leave.
Also, the hardest worker in "kid nation" gets a gold star worth $20,000 for him and his parents to use when he leaves.
I'll probably check it out again next week. The best part about it is that its something clean that I can watch with my wife and kids, so that is nice.