According to this article, the "homeschooling" family recently found to have abused their children significantly had not filed required legal notices, had previously been investigated by social services, and the father of most of the children had previously been convicted of a crime in a plea deal for an indictment mentioning at least four felonies.
In other words, contrary to my previous comments on this matter, this is not in fact a case where a family successfully used "homeschooling" as an aegis against investigation. It is a case where under-prosecution for crimes and failed social services interventions lead to nasty abuse of children.
Really, as a homeschooling dad who values the freedoms we have and also wants to protect children, it strikes me that the best thing we could have is notification of intent to homeschool combined with actually providing social services the resources they need to do their jobs correctly. And as a reader of the "HSLDA Court Report", I can say that yes, that means with a culture of honoring the 4th Amendment by getting warrants and not just threatening one's way into a home.