Seriously, there are a number of reasons why a school would accept someone with a low MCAT score, especially if that person shows evidence of being a fantastic clinician. What if you have an applicant who worked as a nurse for years, and was nominated multiple times for healthcare provider awards? Wouldn't it be reasonable to give someone like that (who has reliably demonstrated an excellent bedside manner and dedication to medicine) the benefit of the doubt? What about a single mother who worked multiple jobs to afford night classes and childcare costs? Would that kind of hard work and devotion cancel out a lower MCAT score?
Personally, I think it does. I'm not saying that all "underdog" stories have to be anything like this. I'm just saying that sometimes people might not have the option of taking prep classes and setting aside large blocks of time to study. That doesn't make them stupid or under-qualified, and I don't think it should be enough to halt their med school aspirations.