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, 25 February 2010
Player A attacks and assigns all his personalities to a province. Player B assigns all his personalities to another province. If Player A resolves his province first, can Player B use the battle action on Reinforce the Gates to drag in one of Player A's personalities and then play the reaction on Stand Down to bow the personality?
Stand Down Battle: Give all attacking Personalities at the current battlefield -1F. Battle: Gain 1 Honor. Reaction: After the resolution of an action that moved one or more Personalities to the attacking side at the current battlefield: Target and bow one of them.
Reinforce the Gates Battle: Even if you control no units at the current battlefield: Target an unopposed unit there. Move the unit to a battlefield with one or more units on the side opposing its controller's.
Zen Faulkes (rules official), 25 February 2010
Player A attacks and assigns all his personalities to a province. Player B assigns all his personalities to another province. If Player A resolves his province first, can Player B use the battle action on Reinforce the Gates to drag in one of Player A's personalities and then play the reaction on Stand Down to bow the personality?
No. The battlefield the Personality is moved to is not "the current battlefield," as required by the text of Stand Down that you quoted.