I had a similar experience at the border plaza in November in SSM, MI. I had business in Sault Michigan and had a so-so stay six months earlier at the Ramada Ojibway Plaza on the Michigan side so I looked for alternative lodging to kill an evening and decided to stay on the Canadian side. I got a good web deal at the Delta Downtown. Anway, I spent the evening there and returned the next morning.

The Nexus line on the US side is only open during the peak of the rush hour and had to go through the regular line. I explained this truthfully. THe agent asked me what I did and where I was from. I answered. He probed me about my hometown (Livonia) and I didn't think too much of it when he told me that he was originally from the neighboring city. Then he asked about my job and requested to see some proof of my occupational licensure as an attorney (which would be totally useless in Canada). I showed him the pocket version of my law license and he sent me on my way but I found the encounter a bit strange. I almost think I had the same agent as the OP. I don't think he looked in my trunk, but if he did it was very brief and I don't recall it.

I agree with the prior poster about clearing both bridges. They are only an hour apart. People in the Upper Lower Pennisula don't hesitate to go to Sault Canada. It is the largest city in the region. If you are willing to put up with the 15% GST, it has better shopping and amenities that most cities up there. I have a friend from Traverse City who plays in the volunteer Sault Ste Marie CA symphony and goes there once a week.

Sault Canada is a working class town, but it has some nice amenities. Because of the Italian immigrants in the early 20th century, it has a nice Little Italy with really good Italian food that is fairly authentic.

Interesting about the "bringing back question." I never declare Canadian currency. We alsways keep $100 in Canadian at home and I always try to return with about that amount.

"What are you bringing in?" is a more difficult question because it calls for judgment. Answering the question: "the car i am driving, the shirt on my back, the underwear on my tush, the socks on my feet, a gruffy pair of shoes, twelve used CDs in my glove box (that I will be bringing back)..... will tick them off, but they can always fault you for not listing something. The fact that it is not subject to duty or restrictions isn't a complete defense.