Sweetie and I have driven across the US border a couple of times within the last few months. I remember a trip a couple years back when we crossed at Aldergrove on our way to Bellingham. The guard practically waved us though. Two women off to Bellingham. Maybe he figured we were going shopping. But more recently, you never know what they're going to ask.
A week ago Thursday, the first thing the US border guard asked was where we were going. That's pretty standard. When I said Portland, he asked how Sweetie and I knew each other. That one caught me off guard! I'm OK at thinking on my feet (or my seat, as it were), but I wasn't ready for this one, so I said we were married. Immediately, I thought to myself, oh boy, now we're in a for a long one. But it wasn't terrible, just a bit tense. He asked us a few more questions, like about our occupations, and then let us go.
You do not mess around with US Customs and Border Security, which is part of the Department of Homeland Security. They do not have a sense of humour. I try to do all the proper deference, but I'm going to have to be ready for more different kinds of questions!
On our way back to Canada, the first thing the customs guy asked as after the usual "where is home" was how we knew each other. Again? WTF? Have you and that blond guy been talking to each other? You're supposed to ask us how much we bought, and whether there are any alcohol, tobacco, or firearms in the car! What with this "how do you know each other" stuff? But these days, we keep in mind that Canada Customs agents are armed. Anyway, this time my answer was that we share a house. It's simpler than getting into the whole marriage thing, even though we do live in Canada where equal marriage is the law.
Maybe someone should offer a service where they would quiz you on potential questions you'll get at the border and coach you on the answers. You don't want to make it obvious to the guard that you're thinking about what to say. At the same time, you don't want to say just anything! 'Tis a dilemma.