I don't know about other parts of the US but here in Ohio there are grocery stores that have member cards that are scanned they will give you a discount on the items on sale as long as you scan your card.
What they are really doing is gathering info on what you drink, wash with, wipe with, read, eat, snack, smoke, use birth control all the thousands of items you buy at the grocery store are scanned and put into a file marked YOU.
I find that pretty upsetting.