I seemed to have stumbled across the answer:
False 'Emergency' TV Warning Sent to Some AT&T U-verse Subscribers
Morning television viewers across several states got a jolt Friday when a radio broadcast erroneously triggered an alert of an emergency warning system generally reserved for moments of national distress. There was no national emergency on Friday morning.
The warning flashed across television screens and broke into regular programming, claiming to come “at the request of the White House.” The Federal Emergency Management Agency said that the erroneous message came about after a syndicated radio show played a series of tones that set off alerts at other radio and TV stations.
“This morning, there was an inappropriate playing of the national emergency alert notification tones on a syndicated radio broadcast,” FEMA spokesperson Rafael Lemaitre said in a statement. “Certain alerts, like the one broadcast today, are designed to be automatically picked up and rebroadcasted by other radio and TV station. FEMA and the FCC are currently working with broadcasters to determine the full scope of the situation.”
The warning was an unpleasant early-hours surprise for some AT&T U-verse subscribers in states including Georgia, Tennessee, Arkansas and Texas, and they took to Twitter for an explanation.
The false warning “was carried on our network, as well as some other providers,” an AT&T spokesman said in an updated statement on Friday. “We apologize to our customers.”
