Not because this thing is particularly rife in schools but because no one will take restrictions seriously while they have to send their children to school.
We're fortunate to be (for the moment) in a low risk area and I don't know details from other areas but here, cases in schools have been isolated incidents and well contained. There doesn't seem to have been onward transmission school.
However, people very much are taking the view, what's the point of SD etc when they're going to school?