@NerrSnerr do you think that all parents of pre-schoolers who are not in OFSTED register nurseries should be routinely inspected as well, and forced to use their however-many-hours-it-is-of free child care if they don't meet the inspector's expectations for what they are doing with their child?
That's the exact equivalent of arguing for routine monitoring and inspection of home educated children. (we home educators can get quite riled up about it).
There are already legal safeguards in place. If a local authority has cause for concern about the education being provided to a child, they have a duty to make enquiries; if they still aren't satisfied that the education is suitable, they can take the family to court for a School Attendance Order. That's the right balance of power: home educators have to be able to persuade a reasonable person (the judge) that there is a suitable education taking place; the power does not reside with local authority staffers, who may have a very narrow definition of what constitutes a suitable education, and who do not know the children in question or their individual needs. A judge has a level of critical distance.
If there is cause for concern about a child's welfare, then that's a matter for social services, who already have power to intervene where needed.
It's a matter of all of us, as concerned citizens, looking out for other people's children and their well being. Every one of the home educated children who has been the subject of a serious case review was already known to the authorities as a concern; in every case, it was failings on the part of the authorities that led to the child's death or serious injury, not the fact that they were ostensibly being home educated.
Within the home ed community, if I came across a family where I genuinely thought there was neglect, then yes, I would report it to the authorities. And the ones who are basically locking their children in a cupboard? No amount of registering and monitoring is going to persuade them to register and be monitored, and - once caught - the fact that their children weren't receiving a suitable education is going to be the least of their worries, frankly. Hard cases make bad laws.