Time for some pedantry!
Re: Orson Welles' War of the Worlds broadcast, the public panic really did happen, though it wasn't a matter of millions of people rioting in the streets. Simon Callow's biography of Welles devotes 10 pages to it. Context: Every day Europe was coming closer and closer to war, and Americans were highly conscious of the fact that we had at the time no system of defense from an air attack. Also, several million people tuned into the broadcast 12 minutes into it--because across the radio dial the extremely popular Edgar Bergen and Charlie McCarthy show cut from comedic hijinks to some operatic songbird yodelling away. A lot of people, in pockets scattered across the country, did take the program literally, but in most cases realized the facts fairly quickly. Here and there somebody would leave their building screaming or run into a public place yelling "We're all going to die!"--stuff like that.
Welles himself had a fairly intense experience of the furore, so it may have looked bigger to him than it would to you and me. First off, there were a slew of angry calls to CBS including death and bomb threats. Then, in the aftermath, the newspapers--already feeling very touchy about losing readers to the competitive medium of radio--were scathing. Many very intemperate words slung about CBS, the Mercury Theater, and Orson Welles. Turned out in the end to be good for his career, though.
One way in which Welles would have been slinging the blarney later in life is if he made out that he deliberately set out to prank the public. He tried to make his adaptation of the H. G. Wells book as realistic as possible, but it never occurred to anyone that it would be taken literally. As usual, the broadcast was cut into ay intervals with the reminder that you were listening to the Mercury Theater of the Air, etc. etc.
So, Welles wasn't fibbin' when he said that there was a clusterfuck, but if he ever tried to claim it gave him his bona fides as Master Prankster, he was just being Orson Welles. One thing the Callow biography makes clear that he did consistently throughout was career was lie, lie, lie his bulky ass off.