I expect everybody involved with this are asking themselves, what if. The trouble is in life sometimes we don't get a second chance. Most of the time we can let things go and get away with it, but not every time.
I heard it was a childs party and the kids and parents were in the garden playing. It was a split second thing and nobody saw it happen. It's sad that this was so easily preventable. There's a few who can take the blame for this and they will have to live it.
I hope , after this, that I won't put things off if they need to be done. We learn from mistakes but this is not the way I like to learn.