alt Hacker News> (Speaking as a parent of three) why can't we just leave all responsibility to the parents?
Then I'm sure that you appreciate that there are both legal and informal checks in place ensuring that you can take responsibility for your children in the offline world. For example: I would be surprised if your children were able to play organized sports without your permission. Failing to ask for permission would deny you the responsibility of protecting your child as you see fit.
Uhm, I am pretty sure kids do not require signed permission to go on a field with their friends and play basketball or football (either the European or American... or Australian one :). And you are likely to not even find out about it unless someone has broken something.
Signed permissions are needed for "organized sport", where there are other adults or companies that can be held liable in case something relatively usual happens (like broken bones in contact sports, but also pulled or ruptured tendons/muscles in non-contact sports...).
So the challenge is: how do we ensure kids enough freedom to do the things which they need to explore themselves, while ensuring no life altering harm of high chance (death/disability/going to jail...) comes to them or they instill on others — and do not have to have them tracked completely throughout their lives.