This is only a flaw insofar as the child-protective services are effective in detecting abuse and the state is a monolithic entity.
My point is that trying to guarantee recursive watchmen does not work. It almost invites looking at that structure as a puzzle to be solved, as a game to played.
A power balance based on mutual trust and mutual responsibility is more susceptible to individual overreach, but also more stable in identifying them.
Who will watch the watchmen? Once the state legislates overreach into law, who will challenge them effectively?