It is interesting that this exact scenario is talked about very widely and quite openly locally. People will organize groups and even short vacations to do things like Christmas shopping. And yet... I've never heard a single mention that it might get you in trouble. You'd think it this was so blatantly illegal people wouldn't litterally "work in Washington" (i.e. live in Vancover) and "Shop in Oregon" (i.e. even their grocery shopping is done in Portland).