It looks to me like they unbolted the two signs in the photo, turned them upside down, and then rebolted them to their posts. Upside down, both signs.
I wonder what that means in Korean culture.
I think we're maybe going to need a Korean War thread.
On Edit, I played with that photo after posting and after blowing it up to huge, I find that the yellow sign is right side up, however I still think the other sign is upside down. What does that mean???