America has a lot of lawyers. (I would know, wouldn't I?) This photo is of a public child stroller at the St. Louis Galleria, a major shopping mall.
You see warnings on all sorts products in this country, "do not put your hand in wood chipper" kind of stuff. Each one means that someone has tried the dumb stunt, an injury has resulted and that person or the family has sued for a bunch of money. So some lawyer told the manufacturer to put on the warning in an attempt to prevent future claims.
What a great country.