The second part of this ruling seems flawed. The card in question says right on it "each of you must invite the other to ally (if legal)", emphasis mine. Wouldn't that imply you could use it, still declare the attack against player B, but then because it is not legal to invite B as an ally, not invite Player B? At which point the rest of the effect doesn't matter. Why does use of this action preclude Player A announcing an Attack against Player B? The Good Faith Rule only applies to the announcement of Actions, not declarations during rule procedures. For this ruling to be right wouldn't the action have to say something like "each of you can not declare an attack against the other." Which would be way more powerful that it should be (even in multiplayer).
Re: Ningen's 'Treatise on the Nezumi'
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.