You can't hide an evac of a large city without detection, night or not.
Artillery accuracy isn't effected by daylight and it isn't just about daylight helping the evacuation, it is about how hard an unexpected evacuation would be if people had already gone to sleep. During winter you might do one at night if you felt it was easier to do the evacuation when most people would be at home but still awake but odds favor it would be easier to evacuate workplaces and schools, person for person, then homes. Most already have safety drills and I don't know but I am guessing in Korea those include 'WWAARR!!!' not just FIRE!!!. If I were them and if I had been doing school drills I'd want to do it during school hours on a school day. Even without the drills, far easier for a police officer or two and the teachers to coordinate several hundred kids then several hundred individual families.
I take it for granted we could not hide an evacuation at any time, but wonder whether daylight evacuation at the cost of inviting an attack would result in less casualties than launching nighttime air strikes on artillery positions BEFORE evacuation in the hopes most could be neutralized, or at least otherwise engaged, before they began firing on South Korea. If it looked like most of the assault were not coming across the DMZ anyway, shelling South Korea would do little but 1) waste limited material needed to defend the Motherland, 2) make Chinas aid more diplomatically difficult and 3) ensure the eventual peace terms were especially punitive.
Last First in wotmania Chat
Slightly better than chocolate.
Love still can't be coerced.
Please Don't Eat the Newbies!
LoL. Be well, RAFOlk.