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, 17 February 2011
Recon Open: Bow your performing Scout: Target a province. During the next battle this turn at that province's battlefield, you have ht eability, "Battle: Choose your performing unbowed Scout: Ranged 6 Attack." Before this turn ends, if there were never any units on the enemy side at that province's battlefield, put this card into your hand.
The relevant text is in Bold for easy viewing. My question is if I play this during my open phase and do not declare an attack will I still be able to put this card back in my hand? Seeing as how there was never a battle at that province I am uncertain whether I would still be able to get it back. The same would apply to the defense if I played this card and my opponent did not attack me would I still get it back?
Thank you for your time.
Zen Faulkes (rules official), 17 February 2011
Waylay the Messenger: (I)f I play this during my open phase and do not declare an attack will I still be able to put this card back in my hand?
No. The card text specifically references "battlefield." If there was never a battlefield, you can't check for units within it to meet the condition.
The same would apply to the defense if I played this card and my opponent did not attack me would I still get it back?
No, for same reason.