Always take General Whiteheads advice, trust me on that one. I may be reading more into your post than I should but I think I detect an element of "that player is not playing the way the Generals did at the time of the battle " in your post. Maybe I"m wrong, if so I apologize. My feeling on that is: of course he is. First of all, we are all well aware of the strengths and weakness of strategy in the late 19th century and we try not to duplicate the mistakes of the time. Secondly, while these scenarios are designed to funnel you into particular places on the battlefield, a good general takes advantage of the expectations of the enemy to deliver the unexpected blow where they are weakest. Thirdly, these are games and knowing how to win the game is not necessarily the same as duplicating historical results (though destorying a rebel attack on little round top definitely has a very satisfying feeling about it on both levels).
