The young man who, at the end of September, 1924, dismounted from a taxicab in South Square, Westminster, was so unobtrusively American that his driver had some hesitation in asking for double his fare. The young man had no hesitation in refusing it.
I think the MFA programs have had a real effect on the state of American fiction, but I don't think it's a question of "this is written by someone with an MFA, and this isn't. " I challenge anyone to identify a book in that way. It's totally impossible.