will it be as empty as Arcade Fire......
Do they let you move to the better seats of its empty?
they don't 'let' you as it would be mayhem, but if a show is less than 70% capacity, making your way to better seat is highly recommended and likely won't be stopped
I have seen artist say something mid-set for all the people up in the cheap seats to come down and fill the front up
This happened to me when I saw Emerson, Lake and Powell at the Cap Center. They had maybe sold the first 15 rows on the floor, with some smattering of fans in cheaper seats. Basically everyone was upgraded to the primo section.
Also, I think U2 was banned from returning to the Cap Center when Bono kept singing "Come on down", and everyone rushed the floor. True story.