I am going to play devil's advocate and disagree. Having dealt with nontrads for the past 15 years, I have had several occasions where rejections where "appealed" or requested for reconsideration that were successful, though not at a UCSF specifically . You have two possible paths
1) You have an uneven, widely varying record, that when averaged, puts you in low end of applicant pool. For example, if you have an atypical background or story that has your first two years of work being really bad, followed by a few fantastic years along with outstanding additional items such as research, then it may be worthwhile.
2) If you have something truly outstanding in a good record that you feel may have been overlooked, it may be worthwhile (this is much rarer than the first)
In either case, you should be able to say this in 2-4 relatively short sentences. Let me repeat that, you should be able to point this out in a just few sentences else it will not have the impact needed to overcome the inertia of a reconsideration. An example may be
"To members of the admissions committee;
I respectfully request a reconsideration of my recent application rejections. I believe that my recent 2 years of 3.8 work after a hiatus of several years away from school, my MCAT of 32, my years of research, volunteering, (INSERT YOUR LIST HERE), best represents my true motivation, commitment, achievement, and ability to succeed in medical school and as a physician. Thank you for your reconsideration"
And now Mr. Speaker I yield the floor