Just have a jammer on school premises and use mac auth for the wifi in addition to the the metal detectors at the entrance.
Much easier to just make your school have some thick walls that prevent cell signals :)
People assume they can reach you by phone these days, especially if you're the parent of young-ish children.
Sure. But in this story the school fell back to the "old-fashioned" way and sent someone along to the guy's house. It seems clear that the guy got along just fine without being reachable via telephone.
That's a non-sequitur. My assertion was that the fellow in the story got along just fine without being reachable by phone. He may have regretted how he came to become unreachable by phone, but he received the relevant information in a timely manner.