As Taigo says "If the action moves any units", does this ruling apply, meaning that is "not treated as a condition for a particular effect, but rather as a restriction affecting the entire action".
Moto Taigo XP and the "If" Condition
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.
Taigo's wording is unfortunate and we're discussing it, but essentially you should only use his ability if, to the best of your knowledge, the action could / would move units. Please take it in a loose sense, though I can't think of a game situation where using Taigo without a movement would be advantageous.