Supermarkets and pharmacies offer discounts when you sign up for their loyalty cards. But every time you swipe your card, you purchases are recorded for marketing purposes. These buying records are now being sold to life and health insurance companies, who use them to evaluate your rates based on your food and nonprescription drug purchases!
Many stores let you sign up anonymously as “Store Customer”. So, if you don’t want your personal data to be used in that way, consider not giving your name when you sign up for a store loyalty card.
Source: Winter 2007 edition of “Bottom Line/Personal” publication