Interesting story. Here is the woman's own blog about the event:
Haiku of the Day
It appears that it was the neighbor (the one whom brought the child home from that park) called the police. Since the police officer who came out (according to the mother's blog) did not file a report, then said neighbor probably also called CPS.
Obviously, in hindsight, CPS should have quickly determined that this is a non-case. However, it is all hindsight. I wonder how the neighbor described the situation to CPS? In such a way that the CPS officer had no choice but to go out and investigate? Or are they under a duty to investigate all reports?
We do see news reports, from throughout the country, where CPS for some area does not investigate some report, or does so poorly, with the child ending up being harmed. Then, everyone screams about the lack of investigation.
I guess that, as it stands, I blame the neighbor more than anyone.