The article you sited stated that the parents put them in the front row. Where parents and children are concerned there is very little difference between put and allowed. It is possible that you and the article are using the term children to mean older teenagers but that what I think of when I hear the term child.

The caption on your article states that the protesters came prepared for the water cannon with tarps, I didn't just make it up.

Like I said I really have no idea if the police behaved properly or not. I have only read the article you posted and brief AP report, which by the way had officials saying that more than chestnuts were being thrown.

My comments were about the parents who either brought their children or allowed them to go. If we buy the silly argument that the tarps were for rain (I guess they don't have umbrellas or raincoats in Germany) people were there intending to chain themselves to trees so they could better resit the police. No responsible parent would allow the children to attend a protest where people were planning to physically resist the police.