Keep Children under Control

This sign was found up in Northumberland about 10 feet away from the edge of a big cliff (maybe a 50 foot drop) down to the sea. I would have expected it to say something along the lines of “Keep of the grass” or at the very least something about the huge cliff. But no, “Keep children under control”. When seeing this and reading this sign I thought to myself, can you ever keep children completely under control?!