Soryn Arkayn
In feudalism the overlord gives a patch of land (the feudum) to the vassal, os that the vassal can have enough income to live and to arm himself as a knight.
When the enemy comes, then the overlord says that 'come here tomorrow armed up' and the vassal goes (with his servants, of course). So veterans can't escape service.
I still say that if units become invisible then the enemny invader
1) is blocked out by an invisible obstacle (1UpH)

2) suddenly finds his army surrounded by several times more units popping out of nowhere.
So that's why I say that they should become visible campsites. Is it now better?