Really?

What's going on here? Guns are outlawed in Japan, how many armed robberies in parks occur in Okinawa? Wait... Lets read this sign, it talks about not doing graffiti and starting fires in the park. But no where does it talk about armed robberies?

Maybe the picture is just a clever way of getting people to read the sign. OR Maybe its a clever way of keeping people from ever coming into the park in the first place.