We find that because the pool of MBA candidates is so anonymous, many perceive any minimal difference between themselves and others as a huge disadvantage. One anxiety that frequently surfaces is that a candidate may have no alumni connection to the school and therefore feels that he/she is behind at the starting line. We can assure you that if you are a strong candidate, you will not be dinged by a school if you don't know any alumni. In fact, the vast majority of candidates will not have direct connections to alumni.
The bottom line is that in some cases, if you know a powerful alumnus or alumna, he or she can help you. However, generally, the standout candidate without the alumni connection will still succeed, and the weak candidate with the alumni connection will still fail. So, focus on defining your candidacy and not worrying about minor perceived weaknesses. You can succeed on your own, regardless of whom you know.