Next time you are in Nelson, B.C., or some other Canadian community...
Stop a dozen or 20 different strangers on the sidewalk and ask, "Can you tell that I am an American?"
I would be interested in your findings.
I'd do it myself, but I'm still recovering from having spent a few days walking around Seattle wearing a big pink button that said "I Know Spokane...ASK ME!"
Sure, that was in a previous century. But I still have occasional nightmares about it.