I am also certain that they do.  On Fridays there is typically a piece of paper hung up on the admissions office stating that they are having a confidential meeting, or something.  I would assume that they are making decisions then.  
If it is like last year, then they will mail out decisions on October 16th--if you read the guidelines carefully, the rule is to not release decisions until "after October 15th"--and you will receive the decision by snail mail.  I interviewed in September as well, and I received my letter in the mail on the 18th, post-marked for the 16th.  It was one of the happiest moments of my life.  After that, I was finally able to withdraw a number of applications and cancel a number of interviews.
The acceptance letters from last year were in normal-sized envelopes, but mine was packed with forms and a return envelope to accept my seat in the class.  They did not require a deposit.
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