1. The fortress must be destroyed.
2. Yes, AH can scoot. This VC is meant to encourage the sort of short term "land grab" offensives that AH pursued and prevent an a-historic "fall back" strategy since it should be obvious to the AH player that he cannot hold on to what he takes.
This is interesting. If possible may
I know what is the source (book) in which they tell about those "fall back" strategy?