When my eldest son was 1, a neighbor called CPS on me. The complaint was that I was abusing my son. Of course, it was unfounded, but if they had done a more THOROUGH investigation, they might have learned that I was being abused by my spouse and intervened.
I have known of people who, for whatever reason, have filed complaints of sexual molestation on other people whom they had some sort of issue against and the children were removed and adopted out, as well. My only hope is that there is a Special Hell for people who use and abuse agencies to promote their own agendas.