At the beginning of the war Del Kemper's battery fired on a train hauling Union troops into Viena, Va, killing several and routing the rest. It seems that this incident caused the Union troops marching out to Manassas before the Battle of First Manassas to go very slowly and carefully for fear of the threat of "masked batteries", ie batteries that were camoflaged and were supposed to be lying in wait around every corner to open up on unsuspecting Union troops.I can't remember hearing about any that actually were used in this way, however. There were several incidents in various battles where a regiment would lie down in the grass behind a fence and wait for the enemy to march close by. Then they would spring up and deliver a volley at close range into their unsuspecting foe, usually with devasting results.I think that actually using efficient camo to deceive the enemy would have been considered unethical by most of the soldiers.-Barrett