Terrifying isn't it. Definitely this homeschooler's worst fear. I'll never forget a case out of NC a few years ago, discussed a bunch here on FR. A naked toddler ran out into the front yard chasing a cat and a passerby called CPS. A social worker went to their house and demanded private interviews with the kids, the family refused and they were in court for four years trying to resolve the issue. The case went all the way to the NC Supreme Court, who found for the family 7-0.
You don't have to be a homeschooler. The biggest mistake is to allow your child into the public school system. They own your child then - you just house them.