As much as I hate to say it, I'm quite sure this kind of behaviour is one of those things that the police have to determine on a case-by-case basis, meaning there is nothing you can really do to stop it from happening. The police are bound by law to act on situations where a person has reported child abuse or endangerment, even if those reports are in themselves suspicious. It's a 'better to be safe than sorry' approach.
Can someone else confirm this is the case?