if the phone is infringing, it doesn't matter where it's sold, but enforcing bans elsewhere would be (legally, right?) impossible…
Not true. If it's found to be infringing US patents, it matters that it's sold IN THE US.
The very same phone could be found to not infringe German/Korean/Russian/Martian patents, and hence keep being sold there.
Anyway, what's I'm really interested in is "did Samsung really copy the iPhone with the goal of having people buy it thinking it is some kind of iPhone", as it has been claimed. As I've written elsewhere here, I'm absolutely against the Apple claims of "infringement" on software, not really convinced about the claims of infrigement on design (for obvious comparisons with what's done in cars or plane businesses... or I'd like to see Boeing banned from making several of the planes it makes to compete against Airbus ;) ), but I do definitely think that if Samsung did try to swindle the general public by selling "iPhones that are not iPhones", then they should be punished.
Of course, I have absolutely no idea if this is even remotely true.... I guess I don't understand anything to/in/of Marketing :D