Hey John:
I know some designers (Huib comes to mind), have built in an
opportunity fire set-up turn for some scenarios... with all units (both sides) fixed for Turn #1 and than released on Turn #2... so players can set opt fire before the game "officially" starts. It works well and is one way to preset opt fire without having to monkey around with game code.
Regards, Mike / "A good plan violently executed now is better than a perfect plan executed next week." - George S. Patton /