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, 28 March 2012
Fukuzo has an open ability that potentially can target my personalities in the discard pile. Can Chugo Seido be destroyed as a reaction to have it target on of my other samurai in the discard pile instead? Normally I would say 'no' but Chugo Seido adds the effect 'at the same location' which would seem to override the normal rules that would restrict the location where I could choose my samurai. Its not performed or anything like that, and fukuzo can (in theory) legally target the other choosen samurai.
Reaction: When another player's action would target one of your Personalities, destroy this card: Choose one of your Samurai at the same location. The action targets him instead, if legal.
Open: Remove a target Personality in any player's discard pile from the game: Fukuzo wears his skin. Until the next time this game this ability is used, Fukuzo copies one keyword, and one ability that does not itself copy abilities, from the Personality.
example scenario: Fukuzo tries to target my clan champion Yoritomo Hiromi. I blow up Chugo Seido to have it instead have fukuzo target my Yoritomo Doho, allowing him no ability to copy and only 2 keywords fukuzo doesn't have naturally.
Brook Cunningham (rules official), 28 March 2012
Fukuzo has an open ability that potentially can target my personalities in the discard pile. Can Chugo Seido be destroyed as a reaction to have it target on of my other samurai in the discard pile instead? Normally I would say 'no' but Chugo Seido adds the effect 'at the same location' which would seem to override the normal rules that would restrict the location where I could choose my samurai. Its not performed or anything like that, and fukuzo can (in theory) legally target the other choosen samurai.
example scenario: Fukuzo tries to target my clan champion Yoritomo Hiromi. I blow up Chugo Seido to have it instead have fukuzo target my Yoritomo Doho, allowing him no ability to copy and only 2 keywords fukuzo doesn't have naturally.
Well, you hit the nail on the head, sir.
A discard pile is not a "location", so while you could react with Chugo Seido to the targeting of a Personality in the discard pile, there is no "Samurai at the same location" to which you could change the targeting, so it won't do so.