They would actually cover the windows every night, so that light couldn't be seen, because the South Korean government has said for years that the North Koreans may invade at any time.
住在这儿的人每天晚上会把窗户遮起来，不让外面看到家里的灯光 因为南韩政府常年一直宣传 说北朝鲜随时都可能入侵。