It's just called a pit concert when all the tables are removed from in the lower stage area.
They take the tables out of the main stage area and make it a mosh pit
Seating from sections a-c are removed for standing room only(pit) areas closest to the stage. There are however still seats in the back for those not able to stand for that long or that don't want to but they are first come seating. VIP tickets are also available with blocked off sections of the stage so there is no crowding and there are table tops and bar stools for those patrons.
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