Question:
The scenario instructions allow ALL Germans to move, even units at reduced effect from outside the Army of the Meuse, so that any real German player will bring up eight regiments of engineers and much more artillery, use the leader and aerial reconnaissance for potential bonuses, and have an approximately 94% chance to take the fortress and completely eliminate its defenders (including almost the whole 3rd XX) during the I AUG combat phase, then exploit move southwestward without needing (given multiple armies of units and ZOC kills, the stray brigade of 3rd XX that starts outside Liege can 100% chance be eliminated in the combat phase)

Answer:
Not ALL Germans may move. The scenario only allows the Army of the Meuse to move. No other forces are available AUG I 14 as they are not listed.

Source:
Mail by Eric Pierce to the Yahoo Europa Mailing List, 15.8.2016