My client is not expecting to be paid and is willing to help people. It may be just me, but I was brought up in an era of saying please and thank you. And everyone knows, in this day of social networking, blogs, etc., the moment you do not help someone, customer or not, your name could be smeared across the net without you even knowing.
I admit there is another aspect I personally have issue with and that is on her Contact Us page, it clearly states "Company Name is an authorized retailer for Brand A, Brand B, Brand C, and Brand D." So why can't people read? The email I mentioned in the OP stated "I bought your product..." Obviously, my client is not a manufacturer, only a retailer.
Maybe I am being too sensitive. I know it is an issue we all have to deal with and there really is no right answer. As the saying goes, "your damned if you do and your damned if you don't."