Sometimes I'm struck by how we're warned or protected in areas that should be common sense. Take chain saws, for instance. We know that they're for cutting things that are very difficult to cut with a Swiss army knife or machete. But for some reason they put that little cartoon of the mutilated hand on the thing.
Though, this may have been where chain saw murders started. I bet someone who couldn't read was going through the garage one day and found the chain saw. The guy probably saw the symbol and thought to himself, "Gads! This machine must be designed to magically help people grow bigger hands! I've got to try this out!" See? He was just trying to help.