In Yemen there’s a joke that in 1994, after the South lost the long civil war, the northern tribes who fought in the war started returning from Aden laden with booty and weapons. So the Yemeni government put up checkpoints to confiscate these weapons. At one checkpoint, a soldier with a Kalashnikov rifle was standing guard and, like any other soldier, was stopping the passing cars to inspect them for weapons. Then someone driving a tank, which he had taken as booty from the battlefield, stopped at the checkpoint. The soldier looked at the huge tank and at his own small rifle, and asked the tank driver whether he was carrying any weapons. The driver said no and was allowed to pass.
Driving in Yemen these days, one may suddenly come across barrels in the middle of a road linking two Yemeni cities, with tribal gunmen ordering the car to stop, despite the military checkpoint just passed.