With a link on a recent post, Five-Cent Nickel resurrects a 2006 post about maintaining security in your checkbook. Commenters remark with amazement on friends and relatives who blithely print their driver’s license or Social Security number on checks, and the discussion produces good ideas for keeping your checking account safe: don’t put identifying numbers on your checks, don’t let others do so, and use initials (J. Doe) instead of your full name.

It was a good post and it got me thinking about one of my favorite subjects: privacy.

Even if we’re careful to keep sensitive information off checks and grind up credit offers, statements, and other such materials, we shed private facts about ourselves every where we go, like a kid with a cold shedding germs. Much of this information is unnecessary for the functioning of our economy and the body politick; a lot of it is just flat nobody’s business. And some of it represents a financial liability.

Strangely, Americans are cavalier about the loss of their privacy. In one blog a commenter remarked that he didn’t care what anyone knew about him and couldn’t understand why anyone else would care. People will blurt out their telephone numbers, Social Security numbers, and driver’s license numbers to any clerk behind any cash register, from Wal-Mart to Bloomingdale’s. Without a thought, they fill in “warrantees” that ask them for identifying information and then ask how much they earn, how much others in their home earn, their level of education, and about lifestyle habits unrelated to the warranteed merchandise. What harm can it do, eh?

Well, besides the fact that some of us find the constant barrage of nosy questions obnoxious, it can do a lot of harm.

Corporate entities, unlike governments, schools, and doctors, are not bound by law or custom to keep your personal information private. When your shopping habits, your medical information, your moments of psychological counseling are tracked by retailers, insurers, and financial institutions, it doesn’t take a subpoena to break that information loose. It can be shared by any corporate partner or subsidiary or by anyone who wants to purchase it. Some of that information could be used to your disadvantage.

Consider the record you lay down with a grocery “club” card. For a fee, an insurance company can learn whether you smoke and how much—how often you buy cigarettes, how many you buy at a time. Even the purchase of a course of Nicorettes will suggest you have a smoking habit. That will jack up your car insurance rates, or, if you neglected to check “yes” next to the “do you smoke” question on the policy application, bar you from buying the car insurance at all. It will make it hard—maybe impossible—to buy health insurance.

Had a few car accidents? Arguing over child custody in a divorce? An insurance company, a complainant in a civil suit against you, or your ex-spouse’s lawyer can easily find out about your drinking habits by tracing your record of grocery-store or club warehouse alcohol purchases. Maybe you have a glass or two of wine at dinner—that would add up to eight or ten bottles a month. Do you really think a jury will believe you never get in your car after you’ve been tippling that stuff?

You say your husband has had a vasectomy. So, uhm…why would you be buying those birth control pills at the grocery-store pharmacy?

We’re talking more than invasion of your privacy here. We’re talking invasion of your pocketbook. Any of these revelations could cost you quite a lot of money. In some cases, such as higher insurance costs and higher costs of credit, you might never learn why.

For most of us, these things are already on the corporate record. We can’t take them back, and we can’t demand that our personal data and buying patterns be kept private. They’re out there, and they’re for sale. Where they’re not for sale, they’re easy to subpoena.

So even if you don’t care about your civil liberties, you should care about who knows your private business.

What to do about it?

Most of the questions you’re asked—what’s your Zip code, what’s your phone number, what’s your address, what’s your daughter-in-law’s maiden name—are no one’s business and do nothing to improve commerce. Do we really need to join a phony “club” to get a fair price on the merchandise? Surely if Safeway can sell goods at a fair price to people who are willing to cough up private information, it can sell goods at a fair price to everyone. It doesn’t need to trace your personal purchases by your name, phone number, and address to know what goods sell and what don’t.

It’s completely beyond the pale to demand that you provide private information. In fact, it’s rude.

A rude practice as widespread as this calls for drastic measures. I’m not asking you to return rude with rude. By and large it’s not the clerks’ fault—they’re just trying to do their job. No. I’m demanding a campaign of disinformation.

Yep: that’s untruth. You are not required to answer some marketer’s nervy questions truthfully. You have to provide true answers to a court of law, to the Internal Revenue Service, and to lenders. You ought to give an accurate story to a doctor, your lawyer, your insurer, and your spouse. But otherwise…where does it say you have to give Safeway, Radio Shack, Cost Plus, Linens Plus, PetSmart, and every other nosy corporation the straight dope? Nowhere! And you shouldn’t.

Albertson’s has already ditched its “club card.” With enough passive resistance from customers, eventually other retailers will get the message.

My Safeway red card is made out in a variant of my dog’s name; her telephone rings at Safeway corporate headquarters.

Other cards simply have a fake telephone number and address. My checks have the same fake phone number printed on them. When I’m asked for a Zip code, I make one up. Any time somebody asks you a question that’s none of their business, give them a believable-sounding but fake answer.

And whenever possible, shop someplace that does not demand to know private information about you. Trader Joe’s and Sprouts, for example, sell most of the food items on my shopping list; whatever else I need can be found at Albertson’s and at local grocers who respect my privacy. If you really want to keep your  buying habits private, pay in cash, not with a credit card, debit card, or check.

Remember: if they don’t have a real need to know, they shouldn’t know.

personal finance