The penality is that you have to pay a lock fee (sometimes refundable if you close) and a credit inquiry shows up on your credit report, which potentially lowers your credit score the next time someone (esp. the new lender you approach) does a credit check.
The penality is that you have to pay a lock fee (sometimes refundable if you close) and a credit inquiry shows up on your credit report, which potentially lowers your credit score the next time someone (esp. the new lender you approach) does a credit check.