An army has to take absolute measures
against looting, S.L.A. Marshall explains (in The Soldier’s Load and the Mobilty of a Nation), or provide a moving conveyor belt which will carry junk to the rear:
Otherwise, what is likely to happen is best illustrated by the classic tale of Sergeant Bourgoyne, a member of Napoleon’s army at Moscow.
When the army quit Moscow on October 19, 1812, Bourgoyne hefted his pack and decided that it was too heavy. So he examined its contents to see what he could discard. According to his Memoirs, he found “some pounds of sugar, some rice, some biscuits, a partly full bottle of liquor, a woman’s Chinese dress embroidered in gold and silver, a bit of the cross of Ivan the Great, my own uniform, a woman’s large riding cloak hazel-colored and lined with green velvet, two silver pictures in relief, one representing the judgment of Paris on Mount Ida and the other showing Neptune on a chariot, several lockets, and a Russian prince’s spittoon set with brilliants.”
But having found the pack too heavy, Bourgoyne could not get out of his mind the visions of the lovely women in Paris who might be seduced by some of these objects. So he did not lighten the pack. He went on his way for another month carrying his treasures. Then at the Battle of Krasnoe he lost everything, including his sixteen rounds of ammunition which he had been unable to fire because the weight of the prince’s jewelled spittoon, and the other loot, had made him less than half a man.
[…]
Under conditions of far greater stress, Maj. Robert K. Whiteley, Medical Corps, noted this trait in human nature as he witnessed the organization of the “Death March” from Mariveles to Camp O’Donnell in the Philippines on April 10, 1942.
There was virtually no leadership in the camp and each man had to think things out for himself. Most of the men were extremely weak from malaria and dysentery. They were told at the start that the march would be about 120 miles, and they were warned that those who fell out would be killed on the spot.
Said Whiteley: “I was surprised at the inability of average men to weigh the relative importance of things and discard every object which meant increased danger. Many started out carrying extra blankets, shirts, drawers and extra shoes. Some carried sewing kits, mirrors, framed pictures, clocks, flashlights and cameras. These weights put many of them in the ditch. They paid. for the mistake with their lives.” They were not the first soldiers to do this; nor, I fear, will they be the last.