II run a very verisimilitudinous game - and you never know what might happen - fighting retreats, hiding, ambush, re-grouping, religious debate, gathering information - any and all of these things might come into play and as soon as I start "faking it" in one situation I might over or under compensate in terms of skills/feats/abilities if I don' recall or happen to not what I decided on the spot for them and then we do get into the range of not fair for the players, because their characters do have to keep track of skills and armor check penalties (and even rations!) and the same things they should have to keep in midn when attempting something their opponents and allies should have to keep in mind as well.