I enjoy the taboo elements of pissing especially the the public and exhibitionist elements of the fetish. However I don't relish the idea of causing real harm or trauma to anybody. As an adult I avoid exposing myself to anyone underage (not just for legality but because children don't deserve to be forced into anything.)
For this reason I don't piss on playgrounds or anywhere else kids are likely to be. When I was underage I did piss much more shamelessly but I did not do so out of malice for children as I did to upset adults.
No unfortunately, in my country this does not seem to be a thing. But I guess in Germany, especially in the Berlin region, people are much more open minded to "crazy stuff" like piss parties..