Walmart has advanced analytics program that includes pre-purchase behavior. https://www.walmartdataventures.com/

I can't find exact mention of it but I believe they use cellphone signals to track individual customer movement within a store, so as a supplier you can get analytics on how many people stopped to look at your new cornflakes box redesign or whatever. This is in addition to all the usual website and cookie tracking that everyone does. And it's all integrated - I remember hearing that if you stop and look at a TV in walmart, and then go browse the internet, you might get targeted ads for that specific tv.

They have all sorts of data on predicting purchases based on local weather or even individual changes in behavior. Target made waves a while ago by being able to figure out if you're pregnant by what kind of soap or supplements you buy. All without a scary barcode card.

In the grand scheme of creepy things companies can do, figuring out what groceries to stock and what coupons to send me is pretty mild.

But if they start charging me extra for being white, I will EMP their whole store.