Since that sign is in English, we can only assume that it is fake or that it is only to keep the gawking gringos out of the way of the workers.
When you post something like this, it is difficult to tell the reality from the propaganda because not one of your posts comes from first hand experience. Every photo, every word, comes from sources outside of your mind and senses, not that they would be better sources, but how is anyone to tell?
Just once, I'd like to see a photo taken by you, a word written by you about something you had actually experienced. The rest of us take the plunge...