SUSANNA CORNETT has a long, cautionary post about privacy and supermarket customer cards.

Using supermarket customer cards to look for terrorists strikes me as futile, but not terribly intrusive — but, of course, no matter what people say they’ll soon be using that information for lots of other purposes, most of them less benign.

Of course, anyone with any sense fills out those cards with names like Henry Wadsworth Blogfellow and reports that he’s a 64-year-old Inuit woman who makes over $250,000 per year, thus protecting his/her privacy while corrupting the database in a fashion that — if enough people do it — will render the whole customer-card enterprise useless. (A few people will object that this is somehow immoral, to which I reply: No, it’s not.)

On a slightly different note, I’d like to see an FTC investigation of these customer-card programs for fraud. I do the grocery shopping for the InstaPundit household, and I’ve noticed that every time a store introduces these, they just mark things up, then “discount” some of them back down to the price they were before the discount card. Kroger, for example, had vermicelli for 69 cents a box forever. Then, the week they introduced the card, it was marked up to $1.39 a box, but “discounted” to $0.69 as a “Kroger Plus Card Savings!” special. I reamed the manager about it, but it was just to make me feel better; I know it didn’t do any good. Perhaps some enterprising plaintiffs’ lawyer will file a RICO action or something.