This March 3, 2017 JAMA Dermatology recognizes the importance of sun safety and evaluates what U.S. schools are doing about it and concludes very little.  The article also suggests that relatively easy things such as application of sunscreen before or during school, establishment of shades, and rearranging free time so it is not at peak sun could significantly decrease UV-A exposure and potentially decrease the incidence of melanoma.

The National survey data from the 2014 School Health Policies and Practices Study show that, overall, sun safety practices were uncommon among schools and that high schools were less likely than elementary and middle schools to adopt several practices. Other school characteristics were either not significantly associated with the adoption of any of the sun safety school practices studied (eg, metropolitan status) or were inconsistently associated with such policies and practices (eg, region, percentage of students eligible for free or reduced-price lunch, and school enrollment).Meaning  Increasing the adoption of sun safety practices among schools is needed regardless of the level, location, size, and poverty concentration of the school..

Source: Sun Safety Practices Among Schools in the United States | Adolescent Medicine | JAMA Dermatology | The JAMA Network