_pack = unitBackpack player;
// replace the backpack by a parachute
player addBackpack "B_Parachute";
// at this time a clone object of the old backpack was created at the foot of player, and real old backpack was destroyed
// just check where the pos of the old backpack
hintc format["%1 %2", position _pack, position player];
an other pack was created at the foot of the unit without variable reference and _pack was destroyed.