First, Britain, where children sitting on steps warrants legislative consideration. Found here, which came from here, but the original article (and important comment thread) is here. I'm just going to say that making steps hard to sit on is ridiculous, and the motive is ageist. This can't possibly need further debate.
And this comes from a blog full of angst, which draws it's inspiration from this and this. Few issues are black and white, but legally sanctioned corporal punishment for kids? Absurd. Harmful. Detrimental. Backwards? Certainly, if major nonprofit childcare organizations can move beyond it, without the benefits that parents have in behavioral policy, we can move beyond this question in regular contexts. C'mon guys, you can give this up, no really.