Actually, it's a long list of games and pastimes the Health Department has submitted in response to a 2009 state law dictating that summer day camps and similar programs offering risky activities must fall under state supervision (which involves having medical staff or at least protocols in place.
Which, I mean.
Kids, right? Kids are impulsive and easily goaded, physically rambunctious yet weak, and utterly lacking in any conception of their own mortality (except in the case of Macaulay Culkin in The Pagemaster, although to clarify he wasn't afraid of tunafish sandwiches, he was afraid of the mercury content in tuna, and for good reason. But I digress). Literally everything children do is incredibly fucking dangerous. It is a miracle that so many of us seem to have survived to adulthood, given how stunningly, irrevocably easy it would be for us all to drown in motel swimming pools in a single unsupervised instant, as almost happens in the Alice Munro story "Miles City, Montana."
So kickball is on the list of dangerous activities along with whiffle ball, freeze tag, and also scuba diving, archery, and leaping through abandoned buildings or playing war games in a vacant lot using dirt as projectiles and construction salvage as shields like in the opening scenes of Killer of Sheep.
Capture the Flag is on the list, too—in 1996, at the sleepaway camp I attended as kid and later worked at, everyone was wildly disappointed when, the owners discontinued the two-hour, full-camp, full-tackle Flag Rush, the centerpiece event of Color War, because kids kept breaking their arms. Everyone was disappointed, because kids love war games; here's Alice Munro again, in "Nettles" (a story where a kid does just straight-up die in a moment of inattention, incidentally), from the New Yorker's 75th anniversary issue, the narrator recalls being a young girl, walking down the river with a neighborhood boy:
There were girls farther up on the bank. They might have followed the boys out from town—pretending not to follow—or the boys might have come along after them, intending some harassment, but somehow when they had all got together this game had taken shape. It was a game of war. The boys had divided themselves into two armies that fought each other from behind barricades made of tree branches and the bulrushes and water weeds that were higher than our heads. The chief weapons were balls of clay, mud balls, about the size of baseballs. You squeezed and patted the sticky clay into as hard a ball as you could make—there could be some gravel in it and binding material of grass, leaves, bits of twigs, but no stones—and there had to be a great many of these balls, because they were good for only one throw.
The girls as well as the bots were divided into two sides. Each girl had her own pile of balls and was working for particular soldiers, and when a soldier fell wounded he would call out a girl's name, so that she could drag him away and dress his wounds as quickly as possible. I made weapons for Mike, and mine was the name he called. There was so much noise going on that you had to stay alert to hear your name. There was a keen alarm when the cry came, a wire zinging through your whole body, a fanatic feeling of devotion. When Mike was wounded he never opened his eyes. He lay limp and still while I pressed slimy large leaves to his forehead and throat and—pulling out his shirt—to his pale tender stomach, with its sweet and vulnerable belly button.