Signs of Hawaii: U Down or Not?

Look closely at this sign, and you’ll spot something out of place. But if you casually glance at the sign, you’d never know any better.

This has to be an alteration, but it looks legit, mimicking the typeface and size. On closer inspection, the modification looks like a sticker or actually two stickers since the trailing “s” is layered. Must say, that’s some detailed work. U down?