You don’t; have to tell me about child services as I was raised in foster homes and the street so know about tem first hand and how they left me in places where violence was the normal and you fought with drunks in those houses at aged 9 to wen you left.
As for busy body well what time did they see the kid the first time? Do you know because I would be worried to see a 6 year old by themselves in a park at night with no parents about and do the parents just drop them off while they go out to dinner and can’t be bothered with their own kids.?
Too many questions before I pass judgment.
I don't know anything about the neighborhood this is happening, but obviously, the parents consider it to be "safe"; or did, before they were harassed.