50 years ago this morning, the Emergency Broadcast System made a huge oopsie, knocking off all mainstream TV and radio communications and scaring the heck out of countless Americans. The EBS was designed to seize the airwaves in the event of a nuclear attack so that the President could address the nation within 10 minutes of the alert.
The EBS ran a test every weekend, but this message was different: The "Hatefulness" was a code word embedded as a signal to broadcast stations that it was the real deal. Each station saw the alert and was obligated to cut into its programming and read a special statement. Well, that's what was supposed to happen. According to this summary, some stations did so, others missed the warning, and some just stopped transmitting without giving the warning.
Chaos reigned until someone at NORAD figured out that the wrong tape had been played. Operators scrambled to find the right code words to signal a false alarm. In a disturbing turn of events, they tried 6 times without success to cancel the alert. They finally sent out the right code word 40 minutes after the initial alert.
The original New York Times story on this event features a thorough explanation of the EBS system as it worked then as well as a series of reactions to the fact that it apparently didn't work in this case. However, the article says that many broadcasters were able to independently verify the message was a false alarm and some just ignored it because it arrived in the standard testing window.
I remember growing up on irritating EBS messages like this one: