There are plenty of deals that you make with vendors/merchants that are given in confidence; a merchant may give you 50% off if you promise not to spread it around. Other than those occasions, "shopkeepers" not only want you to spread around that you shopped there, they actually depend on it and will often pay you to do it.
As a customer, I have no interest in you advertising for me, so it's not comparable. Any information that you spread around about me is likely to give other "shopkeepers" greater leverage over me (which is why vendors don't do this in the real world unless they have some sort of financial relationship with each other.)
As a customer, I have no interest in you advertising for me, so it's not comparable. Any information that you spread around about me is likely to give other "shopkeepers" greater leverage over me (which is why vendors don't do this in the real world unless they have some sort of financial relationship with each other.)