The Definitive Guide to the Tippyverse, By Emperor Tippy

[sonofzeal]

It's one of the listed abilities of Wish. To bring anything from anywhere on any plane to any other location on any other plane. Will save applies. Transport Travelers clause.

Not anything, any creature. Even ignoring that, wouldn't the Weirdstone's own effect block it? The wording of Weirstone is broad enough to include Wish's "Transport Travelers" function. The only question is what "regardless of local conditions" refers to, specifically whether "conditions" refers to purely to physical conditions, or whether it includes magical conditions and emanations under its umbrella as well. I'd be rather skeptical of any attempt to magically transport something out of an area that bans magical transportation, without stronger wording to back it up. As-is, we sort of have an IHS situation where sufficiently-broad interpretations create hilarity, but RAW is decidedly ambiguous on the subject.

(EDIT) Google revealed the weakness to me - you can only PLACE them regardless of local conditions, the caveat does not extend to TAKING them. So even with the most generous interpretation you can Wish something into a Weirdstone's effect, but can't wish the Weirdstone or anything in its radius back out.

An actual invasion is done in a more coordinated manner, but that doesn't alter the fact that you simply can't secure a nations borders when industrial scale teleportation exists.

I still don't think you could bring army-sized populations through in anything like a timely fashion - not because the spell can't theoretically transport that many, but because the logistics involved in doing so become prohibitive at anything past a few people a round. That said, a few highly-trained and magically-powered people could wreak much havoc in a short time, so it's not that huge of an issue.

Really, the difficulty I see is that even with concentrated forces like the Cities you describe, it's actually still too easy for enemies to do huge damage if they wanted. Your forces are concentrated, but so are your other resources, all the key strategic points an enemy might want to capture or destroy. I don't think any garrison could mobilize rapidly enough without additional teleportation and instant communications, and at that point it doesn't actually matter what sort of area they service. A garrison alerted by Sending and mobilizing through a TC or Mass Teleport can potentially service an entire plane with almost equal effectiveness as their home town. At that point, Cities become almost the worst sort of eggs-in-one-basket setup... unless Weirdstones work and you can effectively turtle up.