Drugstores in Brazil are doing it and that concerns me A LOT. Their modus operandi is to ask you your CPF (it's like an SSN, but not that secret and powerful) and, if you refuse to tell them, you are not eligible for some discounts which can reach 40% in some more expensive items. Customers happily agree to give their CPFs, completely unaware they are of the potentially disastrous consequences, and we are not even of…
That's an interesting thought. The european GDPR and I think the california CCPA have some sort of clause that says if you decide not to allow, you have to be treated the same. But loyalty discount cards and your drugstore example should have a way to get the discount without giving up your anonymity. This would be better for society.
I'm going to read it thoroughly within the next days.