If you were a dealer, and repeated information intended to you alone as part of your professional relationship with the sender, at the very least you could lose your authorization to sell Nikon and depending on the original contract, could be sued for breach of contract. The point is, however, that a counter person or salesperson is no more likely to know any more factual information than the other speculation on the forums, which is essentially zero. So far no evidence has been presented that suggests the "problem" is a defect at all or that it is anything more than a bit of dust. There is a lot of assumptions but no reasonable, logical tests have been done, few have even tried cleaning if they have dust. So until someone comes up with some evidence it is a non-issue and Nikon certainly has little interest in replying to every rumor on forums.
Why are people so afraid of doing routine maintenance on their cameras?