I believe a mother in Wales left her car parked on a slope beside a waterway, with her child inside unattended. The infant released the handbrake somehow, and the car rolled into the river. Tragically the child drowned.

We don't have any children, but all this is just simple common sense.

I took parties of forty pupils over to France with two adult helpers many times. I was constantly on the watch for potential dangers. As group leader, I was responsible for all the children and the adults too.
Nowadays I think they do a preliminary Risk Assessment.