Playground equipment age restrictions in Japan

I took the photo in this post in 2013. I don't think it was the first time I saw it, but the first time I thought to take a photo of it. I do remember the first time I saw it I was quite alarmed to see such a notification on a piece of playground equipment. My first thought was that it was entirely unnecessary, but then I thought there may be some value to it if taken as a rough guideline and not as gospel.

Over the years, I have seen it many times since, because in recent years when a new playground is put in at a park in Saitama Prefecture, it tends to have this mark on it. Whereas playgrounds installed before 2010 rarely have such a notification. I came to think it was the norm and didn't really put too much thought into it after that initial shock. But they were discussing the rise of these marks on a television program this morning and it got me thinking again!

One of the panel suggested that these marks are to prevent a city being liable for any improper usage of the play structure. He mentioned America and although I don't think he stated it implicitly, I got the feeling he was referring to the amount of playground related lawsuits in the States. The discussion went back and forth, but the takeaway was the same as my very first reaction to these marks all those years ago - are they really necessary? Moreover, are these sorts of "rules" deterring children from playing freely.