I got the distinct impression that it was an additional hoop some institutions wanted to place in front of you to see if you were paying close attention to the application process. At Wash U, for example, I didn't read the fine print, didn't send an udergrad transcript, and didn't get an interview.
On the other hand, for Duke, I DID read the fine print, DID send an undergrad transcript...and still didn't get an interview. Whatever.
It would be a stretch to think that your undergrad performance is anything more than parsley to the entree that is your medical school record.