Robert, et. al.,
A fascinating line of discussion, which I have also espoused. Of note is your discussion of the sack of B., as Petre (c. 1905) mentions it also when discussing the French's "sack" of Lubeck.
Petre's conclusion is similar to yours, while reprehensible by "modern" standards of the conduct of war, that it was considered (even by Seven Years War standards of conduct) to have been accepted practice that looting, rape and pillage was directly related to the ferocity of the defense. Blucher knew this, and while perhaps being justified to subject Prussian citizens to this, Petre felt that the free and neutral city of Lubeck should have been spared, by Blucher taking the fight outside the walls.
As Mark and others point out the letters we've been posting on the capitulations and other events of 1806, repeatedly speak of the standard conduct and "rules" of war. This standard however varied with rank and social status of the individuals involved.