I don't think it is an American thing vs a European thing that separates the knowledge of black tie or formal events and dress. I could be wrong but I don't believe formal attire is "taught" in European schools.

Perhaps I'll stick my neck on the chopping block (taking some heat off of Tobus) and state that these things are most often learned by one of two ways: 1) It is taught to children by their parents (probably families of upper class, or at least those aware of historically upper class traditions and attires), or 2) it is self taught (by anyone who is interested in this sort of thing).

I have friends and family that are partners in large law firms and accounting firms, and they regularly attend black tie events and own their own tuxedos. Is this a class (upper, lower, middle, etc.) thing? Maybe? Does it make someone that does not own or regularly wear black tie attire less in any way? Absolutely not!