When my son was young, my neighbor and I had this type of arrangement. Her two kids would come over at 7 and play until 8, because she had to get to work. I took them to school. She got off early enough to pick them up after school. We were neighbors, the kids were friends, it worked out beautifully. It is ridiculous for the government to say we cannot be doing this sort of thing.
Oh, and the bit about injury. I had an injury. The boys were playing out in the yard with a tennis ball and rackets. The racket slipped out of my neighbor's kids hand and flew into my kid's face. He required 10 stitches(after I got her kids to school we went in to have him stitched up). There was no issue of liability. We are neighbors, friends and it was an accident. Accidents happen, and insurance handled it.
Accidents happen at play dates when the parents are there. They cited in the article that if the parent is at home, then it is a play date, if out and about it is day care. My daughter broke her fingers on a play date(doing something she knew better to do), I was home, took care of her. If I had been at the store, the Mom would have called my cell, I would have come.
This law is just really bad.