When I was in the Army, I heard of a technique used by ROK (Republic of Korea) troops in Vietnam to interrogate captured prisoners. This may be an urban legend but I heard it many times from different sources. I've also heard it attributed to the CIA.

Take 3 blindfolded prisoners for a helicopter ride. Pick one and throw him out the door. Ask the second guy some questions, listen to his answers, then throw him out the door. The third guy will tell you what you want to know. According to one variation on the story, the helicopter was only hovering a few feet high so the prisoners weren't hurt. In other versions, well...

PS: For those who didn't know, ROK and Australian troops fought alongside Americans during the Vietnam war.