Parish is right. I was well-behaved too, and for that matter, I went to public schools for 12 years in two cities and never even saw a fight. Or vandalism. Or teasing. Admittedly this was the 50' and 60's but I don't think things have changed at either school. And we had one girl who stuttered, and two who never knew the answer, and we all sat their patiently until the teachers decided they had had enough time to answer. Even though in the fifth grade I had heard the saying "Children can be so cruel", I never saw it.
But kids use playgrounds all weekend and after school too.
I think the school should hide snipers nearby and when the teenagers have clearly started to do this, shoot 'em.
The rubber hose idea is good, assuming they don't slit the hose, and most won't. But it should be done on both chains of a swing. Normally the chain is straight during swinging (although you might want to take some slow-motion video to confirm this, and save it for the lawsuit), but even a small change that is applied to only one side could set the swing to rolling sideways and knocking someone off.
Do one swing and see if the hose is stiff enough to keep.... it will probably work the second time, but I'm not sure it will work the first time and if it doesn't, it won't help
OK I don't really expect you to shoot them. Maybe catch them.
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