I think there should also be an *Observers* option for multiplayer battles. Basically, normally during a battle between players A and C ... B, D, and so-on just go about tweaking their decisions and commands for the turn. However, if one (or maybe only both?) of the participants choose *Observers* during the battle start-up, then EVERYONE can watch the battle take place.
However, the Observers cannot talk to the participants, only to each other. The way I figure it is that a Lord can invite their allies/friends/rivals, to send a scout/diplomat to "watch" the battle ... but other-wise its a common courtesy to other players.
Now, to not choose Observe would probably indicate something meant to be done under quiet, low-profile circumstances. However, the final battle between the World's last super powers, while everyone else is just a vassal and bored as hell ... those should DEFNITELY have Observers 