Really, I'd say it's wholly up to you how to proceed. Canonically, the Tsimshian would be in crazy flux right now, and since some details haven't been fleshed out yet, it's really all in your hands. I could see explanation A being that the country's been so rocked by turbulent times that the new government that's only been set up for a few years is still in the mood to "make examples" of folks who border-jump, so they could go in hard and ugly. Likewise, explanation B could be that they know how fragile and exposed they are, the Haida who only recently gained power have a soft spot for underdogs and criminals who aren't actively damaging/killing anything, and maybe they'll just politely ask the team to leave (politely inasmuch that they'll offer them a ride and an armed escort, instead of just going right in guns blazing for a kill/arrest)...along with a stern warning.
Personally, I'd go for (b) right now, because it's a way to get the group back together (and nothing irks me like a split party, in a traditional face-to-face RPG). Show up with overwhelming firepower -- a bunch of guys, a bunch of drones, the skies swarming with attack helicopters and spirits, a few obvious shaman-types, a couple "advisors" standing there with Sioux Wildcat patches on ready to commit horrible atrocities against them -- and a single nattily-dressed government Face who is their way out. Show the party that resistance would be a bad idea, and give them a ride off to where ever their teammate got dumped/deported (after a few guns get confiscated, or some similar slap on the wrist)...
...then have 'em act like Shadowrunners to get back into the country and complete their mission. They'll be appropriately aware of just what sort of overwhelming firepower a government (especially one that still has strong diplomatic and perhaps military ties to the Salish and Sioux) can bring to bear when it's properly riled up, and hopefully they'll be a little more covert about all this. When that government has to wake up like a sleeping bear and can't -- hopefully! -- find them so easily the next time, they'll have a chance to sneak around and do their job...but with an appropriate level of tension/fear/wariness in the air.
A variation on all that would be the Tsimshian military (and some Salish and Sioux allies) swooping down on them like the fist of an angry god...but then -- after reuniting them with the wayward team member, again just to get "the band back together" -- demanding a job from them in exchange for _____ number of days to do their job. Make 'em go on a 'run in order to get to go on a 'run. Extra hassle (and karma) for everyone!