IhromantOne more idea came to my mind. I suppose that fresh mod don't changes the saves. So, if one player forgot to include mod, he will receive angels/wywerns instead of 6-7 native troops. In this case he has two options:
1. Continue game as is.
2. To load BATTLE save with mod included. He could lose some seconds, but actually this happened due to his fault, so everything is fair.
What do you think?
If it works its a great idea of solution situations like that.