I feel like maybe for hazards like this not only should there be warnings affixed, but testimonials from the parents of victims. Some people are just incapable of appreciating these hazards without being [emotionally] brow beat.
Another HN commenter on another thread last week made the point that for some people empathy (and its effect, like understanding that what can happen to someone else can happen to them) doesn't come easy--they often need someone to make it personal. While not quite the same as an in-person conversation, perhaps written, photographic testimonials would impress themselves upon some of those people. Alternatively, maybe pictorial warnings would help to warn children capable of appreciating the risk if brought to their attention.
And amen to that