Many? I doubt it. I went with my family to the parade and no one knew anything. We were living close to Minsk. My uncle was a policeman and one of the liquidators(later time, outer zones) and despite been high ranking officer he didn't know.
Pretty much everyone I knew, knew. Those who did not have a shortwave radio got gossip. Some of the details were murky, but the big picture was clear within a couple of days, way before official acknowledgement.
