Today I finally, finally, finally looked up Omelas, because this sign in the Spring Day music video seemed too prominent to be meaningless.
It turns out Omelas is a fictional utopia, whose peace and prosperity depends on the perpetual misery of a single, helpless child. It’s a trolley problem of sorts, of a city-full of happy people as long as one child is abandoned and alone in the dirty dark, never given even a sliver of kindness. In the story (The Ones Who Walk Away From Omelas), some residents choose to accept this as a necessary evil, while others choose to leave. For the ones who choose to leave, the story says, "The place they go towards is a place even less imaginable to most of us than the city of happiness. I cannot describe it at all. It is possible it does not exist. But they seem to know where they are going, the ones who walk away from Omelas."
It adds to all the other visual metaphors in the music video about the children who died aboard the Sewol and their grieving families. It makes me wonder if that last scene in the video, with the thawing plain and tree, is the place where people go when they reject a society that requires the vulnerable few to suffer on behalf of the many.