I just logged on this forum to ask the same question about the interview invites.
I submitted my application an hour ago and I already got an invite. I was shocked, thought it was a mistake. Then I talked to a friend who used to work at an MBA Admissions office, and she said that her program automatically "filtered out" applications that had no chance based on GMAT, and that it was possible that UNC "filtered in" people that had a decent shot based on GMAT, but she had never heard of this practice before.
Seems odd and impersonal to me. To be honest, I'm kind of put off by this.