Whether someone benefits or not from such credit is almost entirely due to their own behavior. As the seller, I think you have an ethical obligation to deal wit

Whether someone benefits or not from such credit is almost entirely due to their own behavior. As the seller, I think you have an ethical obligation to deal with them openly and honestly and to go out of your way not to mislead them. But it isn't your responsibility to paternalize them if they appear to be adults. Most products can be abused, and this is one. But it isn't necessary to remove hammers from the market because some customers will build unsafe houses with them.