A topic from AEG's L5R CCG Rules forum, copied for Oracle of the Void from a copy of the forum saved in October 2015, so pages it didn't save are missing. Players' names are left out; the rules officials are named. Rulings are as they stood on these dates; later rulings, the rulebooks and the Rules Archive may differ.
A player, 18 July 2007
I own and control a dishonored personality in my current army (we will call it: A), my opponent as a presence.
He plays Unexpected betrayal on A. Since i still have presence and that it targets a card in the Army and that besides it is not "performed" by the personality (the target is not before a ":"): Can i play my own Unexpected betrayal on A? And in this case what happens at the resolution of the battle?
Unexpected betrayal: Battle: Target a dishonorable Personality in an army. Cards in that unit cannot perform actions. During battle resolution, the unit's Force is added to your army's total instead of its controller's.
Martin Lund (rules official), 26 July 2007
I own and control a dishonored personality in my current army (we will call it: A), my opponent as a presence.
He plays Unexpected betrayal on A. Since i still have presence and that it targets a card in the Army and that besides it is not "performed" by the personality (the target is not before a ":"): Can i play my own Unexpected betrayal on A? And in this case what happens at the resolution of the battle?
Unexpected betrayal: Battle: Target a dishonorable Personality in an army. Cards in that unit cannot perform actions. During battle resolution, the unit's Force is added to your army's total instead of its controller's.
Playing Unexpected Betrayal on a Personality you control won't do you any good.
Since you are its Controller, all Unexpected Betrayal will do is create an effect where the Unit contributes to your Army instead of your Army. If the Unit wasn't going to contribute to your Army in the first place, Unexpected Betrayal won't have any effect. The thing it says to replace won't happen, so it can't offer a replacement for it.
If the controller's Unexpected Betrayal effect is applied first, it doesn't do anything meaningful. Then the other player's Unexpected Betrayal kicks in and causes the Force to go to his Army instead of the Controller's side.
If the other player's Unexpected Betrayal effect is applied first, there is no force contribution to the controller's army for the controller's Unexpected Betrayal to affect when he attempts to apply it.