Those are good examples, but I would argue that if a practice is sustainable (and often sustained), it is not problematic. If Amazon wishes to provide Prime at

Those are good examples, but I would argue that if a practice is sustainable (and often sustained), it is not problematic. If Amazon wishes to provide Prime at a loss to encourage customers to buy products which Amazon will make money on (enough to compensate for Prime), is there a problem? Would there be a problem if Amazon offered to ship things sooner in exchange for a promise that you would shop at their site more often (even if this promise plan cost them money)?