Same, broken here. It's my most wanted feature. I'm on galaxy z fold 3.
Same! 
That makes sense. For extra context, the balcony its attached to is a gantry only for sound engineers, Containing only the lights and equipment etc. Audience is only below.
Image is not flipped, I had to turn away from the stage to see this, so I suppose if unfurled it would correctly face the audience when they look at the stage.
Ohh a banner. Right, that makes sense. I thought it might be some sort of pyrotechnics.
So you're thinking "kick out" is just what the banner is saying eg name of a band etc.
I saw this at a music venue. It was strapped onto railings above the audience facing the stage. Says "kick out", is attached by zip ties, looks like a tube wrapped in a durable plastic coat, and looked like it might have a wire running to it.
100% this. Boost is great
Riiiight. Tread-mill. Makes total sense now why we call it that.