I hate the idea of road blocks, but that said here is my take. My guess is that it is not illegals in general they are after. Personal knowledge is that there was a lot of drug running by mexicans that were setting up shop on the reservations. Because they looked just like the locals they could set up shop and no one paid attention. The guys I knew were supposedly legal, but I don't think their freinds were. They even had two drug related murders around Neah Bay in a dispute between them. But..., I think that even that might not be the real truth. The coast is so porous up there, they might have knowledge of some potential national security issues and are just using the local's to cover up their focus. Like everyone said, if it truely was about just getting illegals that would be a terrible waste of resources. I had a freind whose brother worked for the federal government in Yakima. He drove around in a truck that was unmarked except for the government plates. Supposedly one of his favorite pranks was to stick on an immigration agency hat, pull up to 7-11 and watch everyone start running.