The LAW case was VC scavenged as a battlefield discard and VC reused and repurposed as a man-tripped one time only mine or improvised projectile (grenade) launcher.This is an article about traps and mines. It has nothing to do with anti-tank rockets.
It was a favorite Vietnamese improvised expedient. You should give the enemy nothing to use against you, not even a spent howitzer shell propellant cartridge casing. Police your battlefield. Lesson learned.