Way back when, in the dark days of my credit past, the postal service would frequently back a dump truck to my house and unload several metric tons of pre-approved credit card offers on my doorstep. Their snazzy, can’t-miss ad copy printed in a dazzling array of retina-burning Day-Glo ink was all too alluring: “$100,000 Line of Credit with 0% APR for Eternity”? Where do I sign up?

But, like the saying goes: “If it looks too good to be true, it probably is.” I’ll let you in on one of the credit industry’s (many) dirty little secrets: pre-approved credit card offers a myth. Bogus. Impossible.

The reason? Credit issuers can’t pull your complete credit report (also known in industry slang as a “hard pull”) without your express permission. They therefore rely on “soft pulls” which provide them with little more than your name, social security number, address and maybe your employer and favorite color. Soft pulls reveal nothing about your debt, past credit history or anything at all for that matter about your current financial situation.

How then, you might ask, is it possible for credit issuers to pre-approve you without knowing a darn thing about your financial health? It’s not. It’s a marketing ploy like any other: throw enough baited hooks in the water and someone is bound to bite. Fortunately for the lenders, this tactic works for a whole lot of unsuspecting someones. I’m still astounded by how many folks are gamed into believing that, with their 525 FICO score, they allegedly qualify for a 0.9% interest rate!

What’s worse is that every one of those pre-approved applications you mail back leaves a black mark on your credit report that announces to other prospective lenders that you’re in the market for [gulp] an even bigger line of credit. Tally up enough of these black marks, and you can seriously damage your credit score.

So the next time you’re thinking of accepting that “One Time Promotional Super Secret Squirrel For-Your-Eyes Only” credit offer that seems too good to be true, be sure to read the fine print. It also pays to be aware of your credit history and FICO score, to understand your current financial health and, above all else, to opt out of those darn pre-screened credit offers in the first place.