When I crossed the border to marry my boyfriend, I didn't want them to think in the SLIGHTEST that I was moving there or working there illegally, after the rough time I had the first time through (they were confused about my diversion). I had a backpack, nothing else. My car was clean. I went thru in the afternoon on a Saturday this time, instead of 9pm at night. The officer asked me a few questions, I could tell he was trying to trip me up. They are basically human lie detectors. I just replaced "me" with "a friend". IE, I said I was going to my friend's wedding. Staying with a friend. He asked where the wedding was, how long I was going to stay, and so I just told the truth. He waved me thru in like 15 seconds. It was a huge relief.
I didn't bring any marriage, PR, or whatever paperwork with me. Nothing. I also wiped my phone before I crossed, I really didn't want any trouble because of texts, etc... telling people that I was getting married, or whatever inconsistencies they could discover if they deemed my car "searchable" and thus proceed to go thru every possession of mine, including my phone.
Long story short, I had an American friend get kicked out of Canada indefinitely because of a text message about babysitting discovered during her PR application. She wasn't getting paid for it, but they wouldn't believe her, and accused her of working illegally. Edit: I'm not sure why I mentioned that. They love to go thru phones, so make sure you don't contradict yourself between what you tell the guard and what is in your phone.
