Q: My sister signed up online to become a mystery shopper to earn extra income. I tried to tell her it’s a scam but she didn’t listen and now she’s out some hard-earned money. She’s too gullible, so what can I say to make her more aware of swindles? — Susan Sister

A: Dear Ms. Sister: Readers who dislike repetition please feel free to turn the page. My soapbox enables me to churn out the review of certain issues that invade our marketplace when consumers don’t pay enough attention to what’s going on .

Today’s economy makes for impulsive acts, as in your sibling’s case of falling for a rip-off (even though some mystery shopping ventures are perfectly legitimate).

Unfortunately, she’s got plenty of company. The FBI continually administers warnings regarding scams.

Whether the issue is wiring funds to “test” a (non)company’s services to a convincing call or e-mail supposedly from the victim’s bank or credit card company to obtain highly personal information, these crimes are definitely on the rise.

One fairly new scheme deals with a credit card sting.

(As a preliminary aside, all too often one — or more — bad apples can spoil the whole bunch and, subsequently, the public is apt to tar everyone in the field with the same brush.)

Normally, when an individual pays with his or her bank card, the salesperson, server or whomever then returns the card to the payer, who usually puts it back in its safe place and goes on about his business.

However, the FBI’s cyber investigation department tells us to stop and look because a dishonest businessperson may have perpetuated the ole’ switcheroo. Unsuspecting purchasers assume the returned card is the correct one but, in too many cases, it tain’t necessarily so.

Of course, Carilynn or Chester Con then have a fine time spending to the limit before the cardholder even realizes he’s been snookered. The theme here is to always check to see if the credit card you hold is the one issued to you.

I always caution to carefully check monthly statements. Along this same line, be certain you also check each credit card receipt before exiting the place of business. While most restaurant servers are honest folks who work hard for a living, that bad apple can rear his ugly head at any time.

An acquaintance recently told of a restaurant server who wrote in $150 tip on the receipt, which the cardholder failed to notice until much later. Thank goodness, he discovered the action and called the manager who quickly fired the guilty party. Neither victim nor businessman contacted the authorities, which, regrettably, probably ensured the reprobate pulled the heist on another unwary diner in a different eatery.

Consumers must be vigilant at all times. While constantly looking over our shoulders isn’t the most pleasant way to go through each day, we need to carefully examine all documents, listen cautiously to what others say (or don’t), and trust our own gut — perhaps the best determiner of all.

Tax Tip: Older and better. According to Kiplinger’s Retirement Report for 2008 taxes, if a spouse is 65 or older, the married filers can take a $12,500 deduction. If both are this age, the deduction jumps to $13,600. If a single filer falls within this “getting older and better” group, the individual deduction rises to $7,100.

Ellen Phillips is a retired English teacher who has written two consumer-oriented books. Her Consumer Watch column appears on Saturdays in the Business section of the paper. An expanded version is at www.timesfreepress.com under Local Business. E-mail her at consumerwatch@timesfreepress.com