How do you know the kid wouldn't have been hurt or blinded, if they were locked up, they may have broken in, if security stopped them, they may get caught on the tracks, electrocuted, hit by a train. They may have decided to break in elsewhere, go online read how to make explosives and do it in the back garden and still blind themselves, get a knife at home and stab each other, etc, etc.
No, security is to help stop stupid people hurting themselves, the responsibility is ALWAYS with the person who commits the action no matter what retarded society rules try to teach people lately. If every explosive device in the country was left on street corners, unlocked with lables saying they make cool explosions..... if kids don't throw them into fires nothing would happen.
It doesn't matter what something is or how dangerous it is, if people are entirely too stupid to be responsible for their own safety they will get hurt eventually no matter the precautions the rest of the planet takes.
Those kids could have thrown aerosol cans into a fire and been blinded.
This is almost as ridiculous as the kids who decided to cross a train crossing when the barriers were down because they were too stupid to wait and somehow the train company was found responsible.
Who is responsible when a kid CHOOSES to walk into traffic, the kid of the fact that every car hasn't had its engine removed to prevent the danger?