This is a test example of a 'flag rush' in a FIXED-ending game.
1- Let's assume this is turn 18 or 19 of a 20-turn fixed-end game.
The Russians are in firm control of the flag..
2- and the Germans are on the other side of a patch of open ground over which it'd be suicide to try crossing to get nearer the flag..
(noob note- the flag appears neutral to the Germans even though the Russians control it. That's why we can never trust the computer regarding flag control during the game, it only tells the truth when the game is over)
3- So the Germans lay down smoke from artillery or on-map mortars and tanks on turn 18 and/or 19 (his timing must be spot on, bearing in mind most smoke only stays on the map for a turn or two) to cover them as they advance on turn 20; the Russians can't fire at them because they can't see them.
The German plotted his moves to stop short of the Russians because the Russians are too strong to melee with.
4- and bingo! at the end of the game the flag has turned neutral like the Germans wanted, depriving the Russians of 300 points.
NOTE- The Germans made their move on the final 20th turn, knowing the game was going to end this turn.
But if it'd been a 20-turn VARIABLE-ending game, the Germans wouldn't have known when it was going to end, (it might have gone on for another 5 turns), so if they'd made their flag rush in a variable-ending game, they might have found themselves sitting totally exposed out in the open when the smoke clears, to be pulverised by the Russians.
That's why fixed endings are unrealistic and the majority of CM players don't like them.