Good point! Was it because of the flash from the machine guns or the use of tracers?I'm just reading an interesting book about the RAF bombing campaign during WW2 (Patrick Bishop - Bomber Boys) (recommended). Apparently the gunners in Lancasters and similar bombers were reluctant to shoot at any German night fighters they might spot as to do so would give away their position. Not a good idea to fire .303 rifle rounds at an enemy who would reply with 20mm cannon shells.
The Lancaster and the Fortress were my favorite bombers of WW2.