Students across San Mateo Union High School District are locking their phones into signal-blocking pouches every morning this fall under a new bell-to-bell ban, and some say a recent shelter-in-place at Aragon High School has them worried the policy could leave them stranded in a real emergency. The district rolled out the rule at 10 campuses in San Mateo, Foster City, Burlingame, Hillsborough, Millbrae and San Bruno this school year, aiming to curb distraction and push students toward more face-to-face connection.
As reported by The Mercury News, Aragon High School senior Francez Santos worries she may struggle to reach her phone if something goes wrong on campus, saying American schools are not safe enough to roll out this kind of policy during emergencies. Santos is not alone — the outlet reports students at Aragon are broadly concerned about how they would call for help if a crisis unfolded while their devices sat locked away.
How the Lockout Actually Works
The district's board voted unanimously on March 26, 2026, to ban student cell-phone use for the entire school day, and formally adopted the policy on June 25, according to San Mateo Union High School District. From the first bell to the last, personal mobile devices must be turned off or set to Do Not Disturb, locked away, and kept out of sight — a rule that also follows students onto school-sponsored field trips and rallies unless staff say otherwise.
Per the same district materials, the board approved purchasing QuietCase pouches for students on May 7, while San Mateo High School is continuing to use its existing Yondr pouches this year. The Mercury News reports that SMUHSD bought a QuietCase for every high school student; the lockable pouch blocks phones from sending or receiving signals, and students may still bring devices to campus as long as they stay sealed inside. Teachers can unlock the pouches using a school-specific magnet, the Mercury News adds, and the policy also bars personal computers, tablets, watches and headphones — though the district notes laptops and tablets required by an IEP or 504 Plan, or authorized by a teacher, remain exempt.
At Aragon specifically, phones must stay locked from first period through the last, including brunch and lunch, and the same rule extends to school-sponsored outings, per the Mercury News. The Aragon Outlook reports the school began phasing in the policy during the first week of classes, with enforcement of violations starting the following week, and that students with 504 plans or IEPs can seek exemptions through their case manager or counselor.
A Scuffle, a Shelter-In-Place, and Confusion
The anxiety isn't hypothetical for some students. The Mercury News reports that in the final weeks of last semester, two Aragon students got into a fight on campus, and police were called. The school instructed students to take cover in a nearby classroom and stay there until further notice, while the district described the episode as a shelter-in-place in an email sent to parents — though some students told the outlet they were informed it was a lockdown.
Sophomore Ellie Blakely, who was on campus during the incident, told the Mercury News that the school offered little communication while it was unfolding. She said she learned what was actually happening from her father, who happened to be in the area, and that texting him helped her understand the threat and stay calmer. Her account is central to why the shelter-in-place has become a flashpoint for students questioning whether a locked pouch could cut them off from exactly that kind of reassurance.
What the District Says Happens in a Real Emergency
Aragon's new principal, Peter Alvarez, told the Mercury News that the district prioritizes the safety of students and staff depending on the type of emergency. He said that during an evacuation for a fire or severe weather, the school would unlock the QuietCases and give students access to their phones. But Alvarez said students should not use their phones during an active threat or lockdown, and that those hiding should avoid texting or calling parents so the devices don't make noise and give away their location.
The Mercury News notes that the district's emergency policy webpage does not address what happens specifically during an active threat or lockdown. Separately, countywide guidance known as the Big Five directs students to remain in designated classrooms or lockdown locations at all times during a Lockdown/Barricade response, according to the San Mateo County Office of Education. District policy also states that parents can reach students through the school, and that students can call parents from the main office, though it cautions that students may not be able to use their phones immediately once an emergency begins.
Unauthorized device use during the school day results in temporary confiscation, with the devices returned to the student or a parent or guardian, according to Hillsdale High School's student handbook. At San Mateo High School, which has run a similar system since the 2019-20 school year, students lock their phones into pouches at the start of the day and get them back after their last class, per the school's own policy.
Part of a Statewide Shift
San Mateo Union's move follows California's Phone-Free School Act, which Governor Gavin Newsom signed to require every school district, charter school and county office of education to adopt a policy limiting smartphone use by July 1, 2026. The underlying law requires districts to develop and update such a policy every five years, though it calls for limiting or prohibiting use rather than mandating a specific all-day ban, according to the bill text.
The debate playing out at Aragon mirrors a national one. At least 13 states have passed laws or adopted policies restricting student cellphone use in schools, and a growing number of districts rely on magnetically sealed pouches, as reported by NBC News. Some districts have tried to split the difference: middle schools in Marietta, Georgia, keep phones in locked classroom pouches that staff can open with a device when it's safe, while Apalachee High School allows supervised phone use in class and more open access between periods and at lunch, per the same report. Clark County School District in Nevada took a different approach altogether, requiring students in grades 6-12 to keep devices in non-locking, signal-blocking pouches stored nearby in the classroom so they remain accessible in an emergency.
A 2023 Common Sense Media study cited by NBC News found that adolescents receive a median of 237 smartphone notifications a day, with roughly a quarter arriving during school hours — a statistic often cited by districts defending bell-to-bell restrictions. According to San Mateo Daily Journal, similar bans at San Mateo High School and Design Tech High School predate the districtwide rollout, with San Mateo High describing years of what it calls successful implementation.
