Most children would use it with no hesitation at all.
The question is not "do children use this expression?" but "is it actually acceptable in polite society where children may be present?"
My girlfriend tells me off for saying things that I think aren't too bad, then I hear her say things that to me, sound even worse in front of the kids. I've never been able to find out exactly at what level piździ is.
(na bahnhofie is from German and not so commonly used)
But in Silesian?