That was from people who said it happened generally at night in a jungle. On an outpost where people were close the distinctive sound of the Garand clip being ejected apparently did cause the death of more than a few people.

In my experience I'd bet a lot of money that more than 99% of American small arms fire was not aimed. You hear a "bang" and you spray the area. Yell "cease fire", and as JFK said about the Cuban missile crisis, there's always some son of a bitch who doesn't get the message. Fire discipline among American troops was, and still seems to be, non-existent. Only snipers and people behind the lines exhibited it, and it was worth a man's life if he weren't careful. Someone who opened up on a monkey while deep in the boondocks was not very popular.

The AK-47 had many advantages over the M-16 even if Colt spent a fortune lobbying for it. Many people died because of that weapon's inferiority to the AK-47. The things that prevented US people from using AK-47 was the distinctive sound it made, which could be translated "I'm a badguy and I'm over here!" and the colors of the tracers, which also translated the same way. Even so, many very small units headed out behind the lines armed themselves exclusively with AK-47s after notifying their support elements they would be doing that. Contact with your support and/or evacuation could get dicey, but sometimes it was better than advertising that you are an American with an unreliable weapon in their back yard. Especially at night they were useful. IF you were a long ways from home. The confusion that caused often gave you precious time. And if you loaded no tracers it was difficult for them to know if the fire was coming in or going out. Flash suppressors were popular.