We live very close to the local Primary school. The gates to the school are never closed, so in the evenings, weekends and school holidays the playground is used by kids riding their bikes or playing. There are two parks within less than quarter of a mile, and a large wooded area. We are not an inner-city location with no green spaces.
So why on earth do people think it's appropriate to walk their dogs in the school playground? Most do pick up if their dog poos, but obviously you can't do that with pee. There is a sign on the gate saying people who allow their dogs to foul will be prosecuted, but I would much prefer a "take your dog elsewhere" sign - there are plenty of alternatives.