I was in the 25th Infantry Division in Vietnam in 1970. We were west of Saigon in the Iron Triangle.  Before dark, three of us went out from our company's night perimeter to set up a "mechanical ambush". This is a Claymore antipersonnel mine wired to a radio battery with a tripwire. We set it on a trail that showed signs of recent use. The next morning, we went out to retrieve the setup, only to find it was gone! We could only think of two things that could have happened. One, that the VC had spotted the device later, in the dark, which was practically impossible. Or two, that they had watched us set it up. Then, after we left, they retrieved it for themselves! We got back to the company quickly and had to report that a Claymore mine, with tripwire and battery was now in the hands of the enemy near us. To this day, I wonder why the VC didn't just move the ambush a little closer in the direction we would be coming. Or they could have saved the Claymore and just shot us, knowing we would be coming back to retrieve the setup. We wouldn't have been looking and would have walked right into it or them. Sure kill on three GIs.

There would be far too many more opportunities to be killed, both by the enemy and our own troops. Also many friendly fire accidents. You had to watch out both in front and behind.