If they want to paint till 1am or sit out star gaze, they can, they don't have get up early to go to school, they can sleep in as long as they're body needs.
I'm always amused by people who think that routine-less living is natural for human beings and is "what their body needs."
The most natural environment I ever lived in was when I lived in a village in West Papua with no electricity for a month. Very interesting experience and quite fun (apart from the massive spiders, ugh...)
You get up at a roughly "set" time because you hear cockerels crowing and nature noises, and the daylight wakes you up due to lack of curtains. Also, there are tasks to be done.
You wash yourself at a certain time in the morning because there is no privacy so you have be at the river at a time when the men are not there and it's the women's bathing time (if you are a woman).
You need to hang out your washing at times when there will be sunlight, but before they will get contaminated by bugs. So washing and other chores must be done at certain times.
You need to do any detailed work (like handicraft work) during daylight hours because there is no artificial light.
You stay in and sleep during the hottest hours of the day because there is no air con.
You have to get into your mosquito net by a certain time because the little houses let in mosquitos and there are no coils or artificial chemicals for keeping them away (in the days before mosquito nets, smokey fires were used for keeping them at bay, so everyone had to gather around the smokey fire during the evening hours when the mozzies come out).
Eating is done at particular times because everything has to be cooked from scratch and cooking takes time and effort and it is hard to keep food fresh due to lack of fridges--grazing and snacking are the exception not the norm.
The result is that you end up having a surprisingly "defined" little daily scheduled, without ever looking at a single clock.
It is actually quite natural for human beings to live according to a routine. The only difference is that in traditional societies, routines vary by season more than they do in developed countries. Being able to drift through the day staying up at random times and doing whatever for hours on end and then sleeping in is something that has become possible due to things like artificial light, aircon/heating, refrigeration and modern buildings.