Jock, I think it comes from American business wear, different jackets, even though very similar, two button vs three button, for example, are more formal than others based on totally arbitrary distinctions. For many the business wear is the standard that our "fashion" idea's most often come from. So, we see the small differences between, the Argyll, Braemer, & Crail and based on the prevalent attitudes here, we make assumptions. While across the pond all three are for the same purpose the differences are simply tailoring options for the wearer.

Rob