Panzer soldier said:
A smart commander uses all of the resources he has available to him. Obviously the strategy is effective or it wouldn't have you all so bothered.
Wars are not won by the nice, and you can't cry fowl in a fire fight if you are out gunned.
We found the use of I.E.D.'s by the enemy in Iraq to cowardly. I would imagine that the Germans bypassing the Mashinal line, was rather inconvenient for the French. The list of history goes on and on.
You should look at this strategy as just a challenge to be overcome.
As you said, “It's certainly not cheating, since nothing in the rules prevents it.”
So be a truly great commander and find a way to deal with it.
I have a way of dealing with it. This is a game. For fun. Not war. If my opponent were to field a force that had to win by manipulating the rules, I would chose not to play.