I read this short story in a Sci-Fi themed class in school around 2009, but I have no idea how old the story was or who the author is.
The story takes place in a park, that I think was the remains of an elevated freeway as it ran for a few miles above the ground. The people seem to live in a totalitarian society of some kind, as the park is, I believe, referred to as a 'free park' with only 1 rule, no violence. There are floating patrol bots that stun both parties if they engage in violence, but the person on the defensive unfreezes faster so they can leave before the violence starts again. A man throws rocks at a drone until it falls to the ground, he then uses the drone to temporarily disable all the drones, and lets anarchy reign in the park.
I believe he is also explaining to a young man/kid that anarchy only lasts as a transition to another form of government, and in this example it was the strong men forming alliances around a water fountain who took power.