I checked levels with John Oliver before the Mountain Goats on Friday night. In retrospect I should definitely have recorded him, especially since he noticed me setting up and made a funny mention of it.
But my point is that its not just the crowd that will spike levels, but the performer will too, as they mumble, then yell, then speak quietly for a while, then laugh, etc. Its really impossible to get decent levels without clipping at some points, even if you're right up at the stacks.