That was probably the band’s idea, as a way to try to get a decent crowd near the stage. If you’re on a stage with a million watts of light in your eyes, it is pretty much impossible to see past the first couple of rows. A standing pit near the stage gets them people they can see, apart from the people in the $500 seats checking their iPhones waiting for the hits.
I’m not a fan of the band, but I love the thing they did in Seattle, dedicating “It’s A Beautiful Day” to Rep. Gabriel Giffords, with a video link to her husband Mark Kelly on the International Space Station