Thanks, forgot Miller was in the Army Air Force.Still, Von Senger, the German commander maintained there were NO weapons of a heavy sort near the abbey.He was ordered to keep the heavy stuff away.I understand there were civilian casualties of those who tried to seek shelter.
If I remember it correctly, by reading Matthew Parker's "Monte Cassino" it's not as black and white as you describe it.
During recon before the bombardment flashes from binoculars were spotted from inside the abbey or very near to it.
Would you, as the Allied commander, have made the decision to trust the Germans and not bomb Monte Cassino?
Anyways, the Germans were so close to the abbey and wouldn't doubt a second if they needed to enter the abbey for military purposes.
Even before the bombardment it was a fortress and storming it would always have cost enormous amounts of casualties.
Only way to keep Cassino intact (and one of the largest religious libraries in the world IIRC) is if the Allies manage earlier to threaten to encircle Cassino, forcing the Germans thus to vacate the area before any bombardment can take place.