That probably wasn't a patriot with a bullhorn. Rather, it was more than likely a Biden compatriot. How can we tell? Biden had an immediate response to the bullhorn. Knowing his mental state, we can all see that he couldn't have made such a rapid response except that he had been coached that it was going to happen ahead of time. The bullhorn was just another cue that he was supposed to respond to in a certain way. And he responded well.