I do think many people neglect to put the correct amount of money on their FAFSA from "Worksheet B", answering the question "Money received, or paid on your behalf (e.g. bills), not reported elsewhere on this form." My husband and I are basically completely independent, but I'm actually submitting a correction to my FAFSA because my parents do pay my cell phone bill, and they gave us a bit of money when I was between grad school and my job, but I forgot to put that on the Worksheet B number.
Your EFC can easily be 0 if you are living completely off of student loans, or if you live with your parents. But I do agree that people probably mistakenly don't report significant amounts of money that are given to them by parents or other relatives each year.
And for those of us who are only 24 and married and have a dependent, all schools use our parental info to determine need-based aid. Sucks for us. And sure, I'm lucky enough to have parents who can afford to pay my cell phone bill. They can't, however, support me to any real extent, or help pay for tuition, so the less need-based aid I get the more loans I have to take. And I'm betting I won't get any need-based aid, because my husband hasn't yet and his parents have less than mine do. I'm bitter in general about how much debt we have to be in just to be doctors, not because I think I somehow deserve more aid than other people. None of us should have to go $200,000 in debt to become a doctor.