You can't watch your kids 24/7, but can you expect others to be responsible for them?

I am torn with this family and the dilemma of pool safety and regulations.

I think I know the house, it's near where the kid on the pushbike ran into my car, he wasn't their kid.

You can not watch your children 24/7, but can you make someone else responsible for their safety in your own home?

What do you think?