Dan Rodricks: At this Baltimore school, it’s hold the phone while class is in session

Before classes commence each day at Hampstead Hill Academy, the pre-K-through-8 public charter school across from Patterson Park in Baltimore, all student cellphones go into locked pouches. Six hours and 45 minutes later, at the end of the school day, students hold the pouches against a special magnet, the pouches open, and the kids have their phones again.