The wait list did not move last year. I am sure you can find the thread. Of the 20 plus people on sdn who reported being on the alternate list, only one was accepted. Previous years it has moved, last year not at all.
I'm not sure if they're interviewing for the waitlist or not, but here's my 2 cents:
Throughout my entire interview I got the feeling that I'd be waitlisted. My interviewer said: "Your GPA is not bad...*shrug*...your MCAT is not bad...*shrug*...your school is not bad....*shrug*..." He also spent a lot of time talking to me about how the waitlist works, and when they accept off the waitlist.
Then I asked him a question, and we talked for about 10 min after that. In that 10 min I showed him that I was sincerely interested in going to Downstate. I think THAT is one important thing they look for. It seems like they don't want to accept someone that won't matriculate there.