I'm afraid I'm going to have to ask for a reference here, Nightlord. I am aware that sort of exercise is sometimes used in operational planning (though distances sure as hell are measured, to be sure that they're not planning on infantry moving a hundred miles a day or something) but it is not what the military typically calls a wargame. Kriegspiel - the early German military wargames - definitely included random luck, and sometimes even capricious referees. Part of the point of a wargame is to introduce potential problems to make sure that leaders can adapt their plans to a changing battlefield.
While on field maneuvers in the Army, I saw this in action. We were practicing pillbox assaults, so the sergeant in charge directed two squads to lay suppressive fire while a third flanked and hit the weak points with grenades (all simulated, of course). This went fine for the first couple platoons to run through the exercise, but come the third, the company CO stepped up to the sergeant and told him, "okay, when your flanking squad moved into position, the bunker called mortar fire on itself. Your men are down, what do you do?" So actual battle drill practice was interrupted and the troop ended up gaming out a full battle as we went after the "mortars," evacuated our casualties, eliminated the bunker, and drove on. At least while I was in the service, this sort of thing was very common.