Its pretty pointless, they simply deserts. Which is ALOT worse than simply having manpower shortage.
Reason being, for example u have 3 units in the fields, they know their flanks and rears r covered and they go to battle with that in mind. Then half way thru one of them simply abandons their post and fled, the whole battle plan is foiled, they may get surrounded and wiped out or simply dominos affect of mass fleeing.
That is a lot worse than say u only have 1 unit in the field where u have manpower shortage. At least they know exactly what their numbers are and no sudden shock that would lead to catastrophic results.
