Is that really "bad database design"? Sounds a lot more like "perfectly fine design for the original use case".<p>Re/Abusing a customer database based mass mailing tool to send non-customer mass mailings is a new use case, so requires changes either a) on the database side - or b) in the mass mailing tool (to use another database table that is not connected to the customer side of things). I would have preferred b) for many reasons.