Cosmic Iguana - Voice of the Evil Doers

Another Urban Legend. KNIGHT RIDDER:

...more than a month later, representatives from the Air Force, Coast Guard, Department of Homeland Security and Louisiana Air National Guard say they have yet to confirm a single incident of gunfire at helicopters.

Likewise, members of several rescue crews who were told to halt operations say there is no evidence they were under fire.

To be sure, the streets of New Orleans posed real dangers in the days following Katrina. Many rescue workers said they heard gunfire... [*]

That is precisely the problem... you can hear shots, or what sound like shots but they are not necessarily being fired at you.

This goes on all the time in Iraq and is never mentioned. Soldiers hear shots or what sounds like shots, and fire at whoever they think it came from. The casualties are listed as "insurgents" by the military, but may well be, and often are, civilians. Tough luck.