I live in Cincinnati and my younger brother attended that fateful show. As with most attendees, he had no knowledge of the horrible events until he was returning home.
We had a preview of this at an Emerson, Lake, and Palmer show on Thanksgiving Day night 1973. It was at the now-demolished Cincinnati Gardens. This was another general admission show so the crowd was heavy and early, waiting outside on a very cold night waiting for the doors to open. When a few doors did open, there was a tremendous push forward. It was sufficiently intense that my friend's date passed out due to being unable to breathe. We kept her upright and shoved folks away to allow her to come around. We also encircled a very pregnant young woman to keep her safe under these conditions. Terrible.