A Typical Scenario in Korea

So today is a national holiday known as 'Teacher's Day' which is, not suprisingly, a celebration of all things teacher. We are showered with gifts that, for me, have ranged from donuts to socks to tooth paste, and general good vibes are sent our way all day. But here's the catch: we must work all day, while the students all get to leave school at noon. What is the logic behind this? My co-teacher claims it's so all the high school and middle school students can visit old teachers at other schools. I mean, what better way to celebrate teachers than let them go home and relax? I guess that's the westerner in me. (grumble).