Communication is very important in determining behaviour.
There is a world of difference between saying that the head (who may have been infected elsewhere) has tested positive and so (through an abundance of caution) the whole school is being asked to isolate ...
... and being honest and transparent and saying that there is strong evidence of transmission within the school community to such an extent that the unusual but necessary decision has been taken to send all pupils home with instruction to self isolate in order to protect family members and the wider community.
The risk is that parents are being denied information to make rational choices based on individualised risk for political purposes (keeping schools open). And that the decisions made in this context may increase the risk to the community in general and that this may well lead to increased risk of morbidity and mortality of the vulnerable in the community.
It is a huge moral burden to place on the young who have no decision making rights if the stats show increased mortality resulting from decisions made 'not in their name' when adults advocating for them are denied information.
And then there are the staff in schools. There is a world of difference between ignorance/lack of knowledge or information and a deliberate mandated cover up for political purposes.
It is past time to stop treating parents as children and pressurising them to consent to risky behaviour (with the treat of fine) at the same time as using moral pressure to isolate with minimal information.
This whole thing of you have all the information you need, do as your told, when you are told doesn't really wash when parents can communicate directly with each other. This authoritarian style only really works if schools can absolutely control information flow.
I go so far as to say that there is a politically motivated conspiracy of silence regarding teens to actively suppress known contagion to keep things open (because infection leads to mild symptoms) even though this is highly likely to spread to the vulnerable population. We have never been contacted by the orthodontists where DS2 became infected. Probably because symptoms like COVID toes don't count and present too late for testing.
That's where individualism has got us. No understanding that the individual is raised by and lives within a a multigenerational community. No reciprocity - all take, no give.