Grasping the Obvious

Sometimes I wonder why our city officials need to post such signs in some areas, but not others.

I am not sure how someone would dive into this pond with the tangle of growth along the shore. I am also not sure why someone would want to swim in a matt of green gew covering the pond's surface.

I would also assume skating to be out of the question as there is open water, as we can plainly see. Yes, it will freeze over during our winter. But how will a person get onto this pond, let alone change their boots to skates in this tangle of growth along the shoe of this pond?