A flick of a switch

I currently have one of my listings under contract that is scheduled to close tomorrow.  This is a nearly new home.  To my surprise, I just got a call from the lender saying that they need to do a re appraisal because the initial appraisal report did not indicate whether the electricity was on at the time of the appraisal.  Now, I know it was, yet no matter my assurances, the lender said that the property would have to be re appraised.  In other words, the lender is going to pay an appraiser to come to the property tomorrow to flick a light switch.  Furthermore, they informed me that if this silly exercise is not done, that they would kill the loan for a buyer with an 800 credit score and 30% down.  How silly is this???