Recently I went to a gas station and used the pump's automated credit-card payment system.

When I finished filling the tank, a receipt was automatically printed for me — right there at the pump.

I reached for my receipt and found another one besides. It seemed somebody had forgotten to take his receipt. Suddenly, here I was with somebody else's credit-card number and expiration date.

(Not all gas pumps include this information on their receipts, but this was one of the ones that do.)

Were I the dishonest sort, I could have tried to place a few orders online or over the phone with this person's card number.

People give out credit-card numbers over the phone, to clerks in stores and in many unsecured situations. Yet some of these people are afraid to use that same credit card to purchase items on the Internet.

To find out the possible risks involved in using a credit card, I called Citibank and asked about their MasterCard policies. Here is one scenario we discussed. A purchase is made online and the merchandise is never received. What does one do? The credit-card holder calls Citibank and receives a credit for the purchase. Citibank will take up the matter with the merchant who failed to send the merchandise.

Another scenario: Somebody intercepts a credit-card number online and begins making purchases with it. The credit-card holder is not responsible, I was told, for any of the charges made — and Citibank cancels the number of the stolen card and issues a new one.

If one pays by check or cash online, the risks are far greater. If the vendor is fraudulent, the check is cashed or the money received without any easy way of getting the money back.

If a credit-card number is stolen online, at most one is looking at the inconvenience of changing numbers.

So who is really at risk with credit cards on the Internet? Our Cloister Shop at monksofadoration.org/giftshop.html is set up to receive credit-card information using an online secured system. We get the numbers off the Internet and manually enter them into a credit-card terminal to process the payments.

If a credit card is not “swiped,” our credit-card terminal asks for the billing zip code of the credit card. If the zip code doesn't match for the credit card, the terminal informs us. That is why many online merchants are very strict about getting a customer's credit-card billing address to verify that the credit card belongs to them.

Unfortunately, we have found that a number of people, for many reasons, enter a zip code that doesn't match the credit-card billing address.

That, coupled with the unlikely possibility of somebody using a stolen credit card to purchase religious goods, made us ignore the warning when a match did not occur.

A few months ago we received an online order from Indonesia for a couple of Bibles. Now, with international orders, zip-code verification doesn't work at all. We processed the order and sent the Bibles off. Later Global Payments, our merchant credit-card processor, informed us that the card owner never made that purchase. The credit card information had been stolen. Global Payments informed us that we, the merchant, had to absorb the stolen merchandise cost.

So who is really at risk with credit cards? The merchants who accept them.

The bottom line: Don't be afraid to use your credit card to make pur chases over the Internet. Just make sure you know and trust the organization you're giving your number to, and be sure the transaction is secure (if it isn't, a box will pop up to warn you). Happy cyber-shopping.

Brother John Raymond, co-founder of the Monks of Adoration, writes from Venice, Florida.