He thought it was an urban legend, but with a little tape and bit of precision, Rob Cockerham managed to “steal” his own identity. And the real victim could have been his credit score.

Like many adults, Cockerham, an editor from Sacramento, Calif., is no stranger to tons of credit card applications in his mailbox.

He usually ripped them up into tiny pieces and threw them in the trash.

Then one day a few years back, Cockerham tried an experiment. Instead of tossing out a ripped-up MasterCard application (Stock Quote: MA), he taped it together, filled it out and sent it off to Chase (Stock Quote: JPM).

Cockerham thought a few things would send up some red flags when his application arrived at the bank. In addition to the tape job, he changed his address to his parents' address, and added his cell phone number.

About two weeks later, Cockerham’s parents called to let him know he had some mail—and a new $5,000 line of credit.

“I didn’t expect to get a card,” said Cockerham, who documented the tale on his web site.

Although banks often profess dedication to thwarting identity theft, you shouldn’t expect them to always watch your back.

What's more, just ripping up an unwanted application, as opposed to shredding it , can be asking for trouble.

“The problem is, you’re assuming it’s a person who’s looking at” a credit card application, says Linda Foley, founder of the nonprofit Identity Theft Resource Center in San Diego, Calif. “It may very well be going through a computer system on a belt.”

Gail Hurdis, a Chase spokeswoman, declined to comment for this story.

Other credit card companies were also reluctant to talk about their security measures.

“We have a number of processes in place, and we don’t really talk about the measures for obvious security reasons,” says Bank of America (Stock Quote: BAC) spokeswoman Betty Riess. “We don’t want to be giving information to people to go around the system.”

Since Cockerham once lived with his parents, he said it’s possible the address is part of his credit history, but it still didn’t explain the fact that it looked like a Dumpster diver filled out the application.

It’s enough to send you running out to buy a shredder.

“It’s something, like a trashcan, that every home should have,” Foley says. “It becomes a matter of habit. As you’re sorting the mail, you put the shredder right near the trashcan. I just sort as I go.”

One woman told Foley she takes credit card solicitations, puts them in a bowl and pours hot water over them, turning the pile into pulp.

Another smart thing to do is stop junk mail and credit card applications by calling 1-888-5-OPTOUT to get your name removed from direct marketing lists.

“There’s really no reason for someone not to opt out,” says Paul Stephens, director of policy and advocacy at Privacy Rights Clearinghouse, also based in San Diego. “It’s even more compelling that you do it nowadays, because companies are cutting back. They’re simply not giving out great offers anyway.”

Cockerham never did end up using that credit card, and says he got a letter from Chase a year later letting him know that since the card hadn’t been used, they were closing the account.

He has since bought a shredder.

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