Doubly wrong: "I don't think any parent would sacrifice anything to make sure nothing happens to their children"
1. There is something any parent must never sacrifice - it is the children future. If children are not educated in what danger is, what risk is and how to deal with them they will never ever succeed in life. The first really danegerous thing coming their way once they are outside their parents protective envelope and they are done.
2. "Nothing happens to their children" - most cretinous idea possible. Sorry, I would like stuff to happen to my children so that they learn. I do not stand right next to them in the playground and always keep at least a few paces distance. I let them fall and collect the usual playground bumps and bruises so that they do not grow up stupid uncontrollable delinquents who have no sense of danger. People laugh at the two proverbial parents standing next to a child which is trying to climb a tree in a cycling helmet for safety. Guess what, my son went and put his helment himself the first time he tried to conquer the apple in our back yard. At the age of three. I noticed what he was doing once he was already half the way up.
It is the parent's obligation to ensure that the children are not exposed to excessive danger or danger which they are not capable of handling just yet. However, limiting it to the point where "nothing happens" is the worst a parent can do.