The Brief Under a new state law requiring districts to limit device access, Oakland Unified has enacted one of the strictest cellphone bans in the region. Elementary school students will place their phones into a lockbox at the start of morning classes. Students across the Oakland Unified School District, the second-largest school district in the Bay Area, returned on Monday to the classroom for the first day of the school year. Under a new state law requiring districts to limit device access, Oakland Unified has enacted one of the strictest cellphone bans in the region. Elementary school students will place their phones into a lockbox at the start of morning classes.