It would be nice if it was simply made impossible in civ4.
Dunno if many games have this feature, but in diablo2, there is no save game option. No matter how you end your game session, even if it is by a PC crash, the game will simply always save the last moment.
If this would be implemented, the whole thing would no longer be an issue and we could all play our favorite 10 minute sessions without worrying about a thing
In a turn based game with grid squares and where every action has a clear start and end, this should be very easy to implement.