How are we going to ensure that every site implements this policy consistently, when the last policy — which was almost the same — was not implemented consistently?’ one trustee

A handful of school districts across the state already limit or ban cellphone use during school hours or on school property. Boston and Brockton began using Yondr pouches — small bags with magnetic locks — last year. Worcester also recently started implementing an updated policy on students’ use of devices in schools.

San Diego Unified’s board on Tuesday night voted unanimously to adopt a new policy that bans cell phone use during most of the school day.