This is of course exactly what many companies now do. Club cards at Safeway are one example. Instead of your shopping being anonymous with them, they can now easily tie purchase data to an individual. This is done on a larger scale in Canada with Air Miles, every time you purchase something and use your Air Miles card, you gain Air Miles you can later redeem. Of course, it also means that Air Miles knows exactly what you bought, when you bought it, and where you bought it, among other things.
Surveillance cameras are now increasingly common.
In Britain, for example, many ventral areas in towns and cities have literally been blanketed with CCTV, the official reason being to prevent and prosecute crime. The technology to automate data collection is only getting cheaper and smaller. If bad data makes it into the system, it is virtually impossible to remove it. There are often no physical records to check against, and companies are more likely to believe their database than you. Data Retention Slowly but steadily, more information about our daily lives is being recorded and stored.