Supposition: a "replay" replays a battle as it was fought by players (single- or multi-).
Good.
Is it actually so?
I am asking as after a naval battle that my fleet won without loosing a ship, I replayed it just to be amused at watching that one ship that went up in flames and then BOOOMMMM!!!
Wait a second... that's my Admiral's ship!
How's I have him promoted in my campaign and turned into dust in my replay ???