I cannot speak for all the programs and can barely speak for mine (other than personal experience) but our program here (at a fairly-well-known little clinic in SE Minnesota) places a lot of value and selection decision weight on whether we know the person. As in, a person who wangles a clinical clerkship for a month in their fourth year. The word on the street is that it is a sure way to an interview at least and definitely a good experience if nothing else.
Don't know if that helps at all...