Wow! The FAA halted planes at Reagan Airport. (FNC)
They do it all the time.
I make a habit of being "last on" an airplane, unless the flight is near full, so I can pick an empty row. I was leaving town one AM, when, before the plane was loaded, the TSA shut down the airport on "suspicion." Turns out some dude checked an electronic bagpipe through the carry-on X-ray, and none of the screeners would accept his explanation. They saw a PVC pipe with wires inside, and concluded it might be a bomb.
Same idea here. Some bonehead hears something on the radio, and jumps to a conclusion. The media does it daily, although usually without this much detectable and prompt effect.