For the record, I got the email too. But, I'm not going to read anything into it. I've noticed schools tend to send emails to everyone even when it would be better if they didn't. I.e. in early Dec, Univ of Chicago sent NY area applicants info about a meeting with current students for 12/16 and sent out rejections to many of the same applicants on 12/15. Lets hope for the best.
I too, might call Duke to change my request to an on campus interview. I'd like to see the school.