Realistically, what is the worst possible consequence of a supermarket being able to track you? At worst, I suppose you be could be charged more for purchasing a certain item at that particular chain. I highly doubt this has ever happened, since it's bad for business. The usual consequence for getting tracked at the supermarket is getting a discount on certain groceries via a loyalty program, with zero downsides for you.
What is the worst realistic consequence for a government (which has orders of magnitude more power than a lowly supermarket chain) tracking all grocery purchases? As many other posters have noted, it's reasonable to imagine a progressive sin tax: for example, your sales tax rate increases as your purchase more meat or liquor. This has a much more profound impact than anything the supermarket is powered to do as a result of tracking your purchases.
What is the worst realistic consequence for a government (which has orders of magnitude more power than a lowly supermarket chain) tracking all grocery purchases? As many other posters have noted, it's reasonable to imagine a progressive sin tax: for example, your sales tax rate increases as your purchase more meat or liquor. This has a much more profound impact than anything the supermarket is powered to do as a result of tracking your purchases.