Gaeatronics may not be terribly happy with the idea. If the Salish played it smart, they might take Tir Tairngire back as a protectorate just like Tsimshian. If UCAS got wind of the plot, that means that Pacific coast bases start drying up really fast. A concern from the local ambassador may note that if Seattle is the only Pacific port friendly to UCAS, then UCAS may have to defend it even more heavily, which means more troops and an increasing threat of attack right in the heart of Salish territory. The Salish would then find it in their best interest to divide the UCAS attention up and down the west coast. Tir ExPats hiding out in Seattle may want specific territory back, not getting dumped down on the Yucatan.
Imagine if Aztlan did a Heel-Face turn and offered to give up Blood Magic and submit their research to the Draco Foundation as a means to help heal the damage done in the Ute Nation from the Great Ghost Dance. They could flip their reputation and become martyrs over night, having sacrificed their own blood to defend the world against a great magical threat. In fact, you could roll that into a Horizon gambit so that Horizon, Aztechnology, MCT, Shiawase and Renraku all make out from the deal and thus no Corporate Court backlash.
It should be noted that if 5 of the Big Ten back something, there should be absolutely terrifying repercussions.
