There are very few situations when applying for financial aid could possibly hurt your chances for admissions. For your financial aid application to affect your admissions you would need to be applying to a school with all of the following criteria.
In general, you would exclude public institutions since they aren’t likely to provide generous financial aid. The exception would be for students applying to popular out-of-state schools. Such institutions often expect out-of-state students to pay full-price. According to survey by the National Association for College Admission Counseling, only 10% of private schools and 2% of public schools are “need conscious” in admissions.
Any school where a student is likely to be among the last admitted isn’t likely to receive generous institutional aid anyway. At this point in the admissions process, given two students with equally below average qualifications for the institution, the committee has incentive to opt for the full-pay student.
Low information admissions process
The committee would have to be using the fact that students applied for financial aid rather than the actual EFC figure for determining need. This is possible but it seems that a stated “need-aware” school would have immediate access to the EFC as part of the process.
Ultimately, if you don’t think you’ll qualify for any need-based aid, there is nothing preventing you from applying for financial aid after you have received the admissions decision. This would still allow you borrow through the federal loan programs and apply for work-study jobs. However, this strategy is only viable if you’re prepared to pay the full cost of attendance.