Last Friday WGN anchors Larry Potash and Robin Baumgarten cut to live footage of what they thought was a small plane crash in the middle of downtown Chicago—which would be HUGE news, except that it was actually a staged crash for the TV show Chicago Fire. Whoops.
From TV Guide:
A Chicago Fire Department spokesman told the Chicago Tribune that information about the fake plane crash was not distributed to everyone who should have known about it. “It looks like it didn't get filtered down to everybody," Larry Langford said, adding that some patrol officers didn’t know about the shoot either.
(I'm pretty sure the "sad trombone" sound at the end was furnished by the people who uploaded the video.)