Great answers below. It is correct that no lender has any recourse if a borrower decides not to follow through with closing a loan. However, the comments regarding the three days right of rescission are a bit misleading. RESPA only requires the three days right to cancel on owner occupied properties. The law does not apply to second homes.
@Steve nailed it...any lender/loan consultant can "Say" anything...loan rates move constantly. The rate quote provided at 9:00 am may mean nothing at noon of the same day!