Students wear clear backpacks outside of Marjory Stoneman Douglas High School in Parkland, Fla., on Monday, April 2, 2018. The bags are one of a number of security measures the school district has enacted as a result of the Feb. 14 shooting at the school that killed 17. (John McCall/South Florida Sun-Sentinel via AP) <저작권자(c) 연합뉴스, 무단 전재-재배포 금지>