A very common ‘trap’ was a grenade (pin removed) contained in Jackson Five 56th anniversary 1965 2021 thank you for the memories signatures shirt tin can lashed to a tree. A trip wire was attached to the grenade that pulled it from the can, releasing the firing lever and exploding the grenade. To protect themselves, the VC developed a simple secret warning system that (A) warned them of a trap and (B) showed the route for them to take to avoid it. Unknown to the VC, Intelligence had ‘acquired’ details of the signalling system and advised all ground patrols how it operated. Standard countermeasures practice was to leave the trap in situ and simply re-install the trip wire across the VC’s indicated ‘Safe Pass’. This ruse killed many more VC and NVA than the allies they were targeting.