Dwight it was about as "impromptu" as those "happenings" in the 60s and early 70s. Those Marshal amps just didn't appear in the middle of a park. I think the moving part of the food court video is how the "civilians" earnestly joined in with the instigators.

Every normal man must be tempted, at times, to spit on his hands, hoist the black flag, and begin slitting throats. H. L. Mencken