When I applied for transfer to the Ivies, I experienced the same thing. I had already been independent for eight years, and my mother had (very recently) built up her business and started earning enough that I didn't qualify for the new financial aid packages that the Ivies offer. I even received a rather snotty email from Harvard after my acceptance that basically told me that I should blame my parents for being "unwilling to help" me continue my education, regardless of my age. It didn't matter that to this day, she has not paid for my undergraduate education, my books, my rent, or well...anything. I don't expect it from her (especially now that her situation has changed dramatically), but I don't think it's fair that medical schools to use parents' financial information when it is clear that a student has been entirely self-sufficient, and will remain so throughout medical school. I'm an adult, and it's unfair for anyone to assume that my parents are responsible for me long after I turned 18 and moved out on my own.
I'm applying next cycle, and when I apply I will have been on my own for twelve years. Everyone applauds my decision, but I am financing medical school, like undergrad and life in general, with no help from outside sources. It makes no sense to me that they require financial information from parents of independent students.