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 October 2007
Suppose I have a unit that contains Untested Scouts, and I use their Limited action on a province. Recon Limited: Target a Province. Until the turn ends, after engaging in a battle at the province's battlefield, you may take one additional Battle action to play a Terrain from your hand.
Suppose I assign a unit to that province during the attack, and I have a Sneak Attack in my hand I would like to use, as well as a terrain I would like to play, and would also like to perform another battle action in the battle (the specific terrain for this example will not matter). Reaction: After engaging in a battle: The Attacker has the first opportunity to take a Battle action or pass during this battle. Play then proceeds in turn order from him.
Which of the following are legal assuming the opponent does not interfere with any actions/reactions? Situation 1: I take an additonal battle action to play my terrain off of Untested Scouts' ability. I then play Sneak attack. I then get the first battle action this battle instead of the defender.
Situation 2: I play Sneak Attack to change who goes first for normal battle actions. I then get my additional battle action from Untested Scouts and play a terrain. I then take the first battle action in the battle.
Situation 3: I play Sneak Attack. I take the first battle action in the battle. I then get to play a terrain off the additional battle action from Untested Scouts.
I think 1 and 2 are legal, while 3 is not. (the reason I list both 1 and 2 as separate examples is because of the existance of cards like Reinforce the Gates which can negate actions that might otherwise not be negated if the opponent knows that other actions might be better targets for negation later on).
Martin Lund (rules official), 18 October 2007
D. Apply any delayed effects that resolved previously and are timed to the trigger (such as, “After the next time this turn he assigns…”) The active player decides the order in which more than one of these effects apply. If different sources each give multiple delayed effects to the same trigger, the active player decides which source's delayed effects apply first, but multiple delayed effects from the same source all happen before delayed effects from the next source happen.
Example: If two delayed effects on the same personality say "After he assigns, dishonor him, and his controller loses 2 Honor," the effects apply as follows: dishonor him, lose 2 Honor, dishonor him again, lose 2 Honor.
E. Apply any triggered traits on cards. The active player decides the order in which more than one of these effects apply.
F. Reactions may now be taken following an action round procedure. Starting with the active player, each player in turn order has the option to take a Reaction to the trigger or pass. When all players pass consecutively, no more Reactions to that occurrence of the trigger may be taken.
Untested Scouts and Sneak Attack are both timed at "After engaging," so:
The effect of Untested Scouts is always applied at Step D.
The opportunity to play Sneak Attack always comes at Step F.
Untested Scouts always comes first and runs its course before you get to Step F where you can play Sneak Attack. Both will have their full effect and not step on each other's toes in any way.