Well, hypothetically, if this went to court, you wouldn't argue about exactly what Cummings did as I'd agree that is irrelevant.
But if the Prime Minister and various members of the Cabinet went on record in that context saying that parents can of course act reasonably in the best interests of their children, that does extrapolate well to this situation. Parental agency to do what is right for your child is an important concept.
It's very reasonable to be wary of exposure to a pathogen in a pandemic, especially if there is clinical vulnerability in the family. Especially if this is for a short time to assess how things will go with the return of 8-9 million children (plus teachers) to schools. It is unreasonable for the Government to insist that all pupils return without adequate safety measures and in fact it is a dereliction of duty on their part not to make better provision for the clinically vulnerable.
This is a highly infectious pathogen which can quickly grow exponentially in numbers if given half a chance, which it will certainly have in schools. It doesn't matter that current numbers are quite low, the virus is seeded through our community waiting for the opportunity to sprout anew. We have no idea how this agent is going to behave in the British winter, alongside the usual respiratory pathogens.
I have absolutely no intention of deregistering my kids at this stage, why on earth should we. But one child probably won't be going back straight away and the other one will be pulled out of school if local infection numbers increase.
And I am delighted that my GP (and potentially it seems also my MP) are being supportive.