damn what an asshole. i work in retail also and there is just something about people that they either want something for free or right now when we are out of stock. the thing that beats me is that its an injector that nobody will ever see. if it was an intake or turbo manifold i would understand a scratch, but an injector? something was definitely up his ass. also you did the right thing of telling the customer. usually when you point out a flaw so small they dont really care or are glad you are trying to satisify the customer by making him happy.