Merchants generally want as much information as possible about their customers so they can more precisely target offers to them. But in our information-centric society, where billions of bits of information can easily be collated and distributed, it’s not necessarily in consumers’ interest to have a lot of their personal data accessible. Seemingly innocuous customer information obtained from consumers at the cash register or online can be combined with data from other sources to obtain a surprisingly detailed portrait of an individual customer. 

Is it possible that in the not-too-distant future an insurance company could check the choices you make at the grocery store and penalize you if you bought, say, cigarettes or high-fat foods? Or, could law-enforcement officials scan store records to see if you acquired materials that could have been used in a crime?

The answer to the second question is “yes”.