The United States Coast Guard regularly patrols the waterways around Washington, D.C. Its cutters communicate with each other, and with the agency's Washington Field Office, on a radio frequency of 157.050 megahertz. Most of the time, the radios are broadcast in the clear, and most of the transmissions are analog, which means that almost any commercially available radio scanner can pick them up. Often, the Coast Guard operates on frequencies designed as "Marine" -- which civilian boats, equipped with transceivers, can monitor and use as a way of calling for help.
It's not clear whether the boats in question were the boats seen on television as the alerts began to panic newsrooms all over Washington. From the perspective of a cable executive producer or assignment editor, a few trigger words -- "shots, President, motorcade, 9/11, Pentagon" -- are pretty much all it takes to get something on the air. That's unfortunate, of course, because scanner traffic, unless very carefully monitored and cross-checked, isn't always as accurate as it might seem. Most other news entities were careful -- they checked in with their sources, including at the FBI, the Secret Service and the Pentagon, and they found that no one knew anything about an incident. Most elected to be careful.
"There were Coast Guard boats were operating in the vicinity of 14th Street and Memorial Bridges this morning. Whether or not these were the same boats using the marine radio frequency used for training purposes has not yet been confirmed," the agency said in its statement. "The best way that we in the Coast Guard can remember Sept. 11 and our security obligations to the nation is to be always ready and this requires constant training and exercise. To ensure the appropriate readiness posture we conduct training scenarios across the nation on a daily basis."
According to a person who listened to the training exercise, the Coast Guard was broadcasting on "Marine Channel 81A," 157.075, which is designated for "government use only." According to CNN's transcript of the radio traffic, one of the Coast Guard officers used the word "scenario" at one point, but the context was difficult to ascertain:
:24 you're approaching a coast guard security zone
:50 you're in a coast guard security zone
1:50 If you don't stop your vessel you will be fired upon. stop your vessel immediately
2:00 If you don't slow down and stop your vessel, and leave our zone you will be fired upon.
2:18 still in the zone, still in the zone
2:25 someone saying: bang, bang, bang
2:35 we have expended ten rounds, the vessel is operating at stern. we're going to reassess the situation.
3:20 this is the coast guard, have everyone go to the stern, place your engine in neutral
3:35 _____ out of play, _____ out of play, break scenario, break scenario, break
Aside from scaring the bejebers out of everyone, erroneous reports can create a cascade effect that turns a mistake into an emergency. Case in point: the Federal Aviation Authority, based on media reports, immediately shut down Reagan National Airport, causing a traffic jam in the airspace around Washington, which is always more dangerous for the planes that are waiting to land. Another law enforcement agency that patrols an island near the airport also took precautionary measures relying on CNN because the Coast Guard had no information to give.