For quite some time, a well established grocery mega-chain here in town has had a customer rewards program. They call it “Club Card” or something similar. Being a member of this program can result in 50% off items you purchase – the aggregate discount on a typical large shopping run can be around 10-20%. Not insignificant. As a result, participation in this program is very high – I would guess that it is over 80% based on casual observation.
There is definately a problem with this program though – it represents a security problem since you can get your discount only by indicating your unique shopper profile. This is accomplished by either letting the clerk scan your member card or by telling them your home phone number. Most people do not carry the card and opt for the phone number option. This means that you are forced to reveal your phone number in front of a large group of strangers.
It also occurred to me tonight that the point-of-sale system personalizes your receipt by printing your name at the bottom if you have used your ‘Club Card’ to make the purchase and get the discounts. This means that it is suddenly quite trivial to find out someone’s (potentially historic) phone number and name by using their number in an alternate queue or at an alternate store. Just to test this, I decided to repeat a number that I heard in the adjacent line when I was checking out and I was presented (at my departure) with a reciept containing the name and phone number of the young lady who recently purchased something in the other aisle. Not good at all. Worse – her phone number is unlisted according to the local ILEC but I have it thanks to this grocery chain’s lax handling of customer identifiers and data.
Makes you think a little and if you are bothered by this, you had better either pay more for your groceries, shop elsewhere or continue to use the card that the store provides to you in place of your phone number.
Update: A few people have pointed out that the administration of this sort of program in this manner would be illegal in the EU. Additionally, some folks have been quick to chime in with the fact that the corporation is really just after a key that they can use to locate the record and that a few people use meaningless keys without objections (for example +1.866.555.1212). This likely means that the clerk or data entry operator are unaware of the 866 area-code [unlikely] and 555 exchange [more likely]- or don’t care. Outstanding (as Ekr would say).