It's a fair question. n=1 but most of the people I know who matched in NC ranked it number 1 because they wanted to stay (for personal and family reasons, etc.). there is also selection bias because part of UNC's mission is to train physicians who will care for the population of North Carolina. They try to accomplish this in several ways including admitting mostly in-state students and providing incentives to stay in NC (the FIRST program, for example). There is also a very supportive culture for students pursuing primary care specialities, in contrast to places like Harvard which don't even have a Department of Family Medicine. But at the end of the day, i think that people matching in NC choose to do it because it aligns with their goals not because they don't have other options.