Comment by zeta0134

The answer is loyalty programs. I wouldn't be surprised if many existing loyalty programs already violate this law in spirit. The customer is encouraged to scan their app, and offered personalized coupons. Anyone not participating pays the base (highest) price possible, and those who are price conscious get a tailored discount, which is not necessarily the same discount as their neighbor.

(As an added bonus, the data stream from the loyalty program is attractive to marketing teams. Want to not be tracked? Higher prices for you!)