Washington, D.C., TV station WTTG-TV quoted liberally from police scanners on its Twitter account during coverage of a mass shooting Monday at D.C.'s Navy Yard.

Quoting from police scanners during a breaking news situation may be tempting, but it's a really bad idea, as the information passing through such devices is not confirmed (and authorities generally don't have time to confirm it).

During the Boston Marathon bombings manhunt, a "false-information feedback loop" occurred after police repeated bad information they'd seen on Twitter.

"Most responsible journalists don’t report as fact what they hear on the scanner,” Poynter's Kelly McBride said at the time.