Shadows of North America does have two paragraphs on Boise plus one Shadowtalk comment. It talks about how Boise has had a rough century, ever since it was depopulated after the Treaty of Denver. See p 123:
"Originally the Cénesté claimed the city, but after a short fight with Salish loyalists they were forced out. Today the southwest corner of the city is technically in Tir hands - but this is more a polite fiction used to justify a large tax and duty free merchant zone."
So I somehow managed to read this section twice and entirely skip those two sentences each time - I guess my eyes were searching for "Tairngire" or "Ute" keyword (the source for Ute/Pueblo presence do seems to be
6WA though).
Understand that international finance and corporate law is bloody complex. Stuffer Shack may well be a corporation that is entirely owned by Aztechnology, but it is not Aztechnology, e.g. 'Aztechnology's Stuffer Shack'. The PCC doesn't want the AZT in its territory? Great, AZT can't be there, AZT troops can't march along the fence line, AZT guards can't stand inside the door with their assault rifles. That doesn't necessarily mean that Stuffer Shack, the wholly-owned corporation which itself might achieve a AA rating, is banned - because The Shack is not necessarily considered Aztechnology Corporate Property, any more than the local McHugh's franchise is the corporate property of the McHugh's Corporation.
Using a subsidiary is so easy (either by creating a new company or buying an existing one) that is actually very rare, at least in real life, for the law to be naive enough to not account for this. Things like operating licenses usually require disclosure of ownership and changes in ownership or in less stringent cases, only foreign ownership. Bans then extend to any controlled subsidiary and possibly even independent subsidiaries. In the most stringent cases (like, for example, US ban on Iranian business),
any business relationship can get you blacklisted, so as to defeat a lot of shell companies tricks.
There are ways to hide ownership. It can be as simple as setting up an intermediary level of separation with another subsidiary, if possible in a country that would shun legal requests about ownership. On the other hand, authorities may also deny operating licenses whenever the ownership trail looks suspicious.
Another methods is to have a completely separate company owned by one or several straw-men that would happen to be loyal former employees. The same same people would then set up another independent company in another country that will be used to channel profits to the parent company.
Overall, the biggest the operations, the more likely it will be subject to thorough inspections. It's one thing to set up a ten-employees shell company as a cover for black ops, and another to own a dozens of malls racking millions in profits around the country.
Also, hiding ownership excludes the subsidiary from the benefit of the parent company extraterritoriality among other things. Megacorporations are supposed to rule the world economy because extraterritoriality gives them an edge over the competition and because they have capabilities that are unavailable to smaller competitors (like paramilitary security forces, Matrix and magical assets...). A hidden subsidiary is not going to benefit from any of those - so it'll be playing the same game local companies and multinationals are playing, and likely losing it to other megacorporations.
