HI LEJ, I agree entirely that it would be very difficult to portray small group tactical manouvere, and if you tried it would not mean a lot to a viewer. That was what I was trying to say. I think that the contrast you note in your examples: "Gettysburg" and "The thin red line" are good examples of what I was getting at. The film maker had a particular point of view which they wanted the viewer to take away, and to achieve this they used artistically valid "distrortions" of actuality. That is quite natural and I would argue ethical, because it is clearly takes place in an artistic context and tradition where it is accepted that this is necessary and beneficial. What would be unethical would be to present the result as an accurate re-creation of battlefield conditions as experienced by a participant.
The reason I raised this issue was because of Banjers comment that "...The fact that something was not present during the historical period that a movie represents, but is shown anyway in historical context makes one wonder how accurate the rest of the movie is...". Given Banjers interests I can understand his concern for accuracy, but that is not the point of the film, if using an anachronistic tune sets the scene better than a contemporary one it is valid in the film's context. As a simple test, probably 80% of the films audience outside the US had no idea of Gettysburg place in the US civil war. Would the film have been any less successful in its artistic intent if it had shown the Confederates as victorious? Personally I don't think so. However I also think that those 80% would have gone away believing that the South had won, and it is the lack of critical analysis and willingness to apply an appropriate intellectual framework to differentiate between an artistic viewpoint and an historical one that concerns me, and I think diminishes both art and history.