It's print advertising's tiny type, fit for reading by mice, or a speed-talked disclaimer on TV or radio that often makes an advertised claim false or misleading.
"FREE BOX OF CORN FLAKES ... with purchase of a box at regular price."
Companies selling cable TV packages, cellphone service, restaurant food or just about any type of retail good or service might be guilty of it, said Edgar Dworsky, a former deputy attorney general in Massachusetts, who tracks such advertising fibs at MousePrint.org.
"Companies like to put the happiest face on their claims, but they know if they really told the truth in the big print people would be less interested in the offer," said Dworsky, also founder and editor of ConsumerWorld.org.
Marketers think it's OK to say almost anything in an ad as long as they reveal the truth with an asterisk,
Dworsky said. A fair-advertising rule would be simple: "The fine print can't change the meaning of primary claim," Dworsky said. "But unfortunately, I see advertising that does this every day."
Here are questions and answers about mouse print.
Q. Where am I likely to find mouse print?
A. "It's just all over map," Dworsky said. "If they advertise, they probably have fine print. I can't say one industry does it more than another."
Recent examples include Best Buy's new policy to match online prices, which sounds great. Fine print reveals Best Buy will match prices of a few specified online retailers, only on certain categories of products and it will exclude some of the best sale days, such as Black Friday.
Others are T-Mobile's "unlimited nationwide 4G data" service that comes with limitations, Excedrin pain reliever products marketed under three names but containing the same active ingredients and an Avis offer for $30 off "your next Avis rental," which applies only to a weekly rental, fine print reveals.
The inside back cover of Consumer Reports magazine, in a section called "Selling It," is another great source of mouse-print revelations. Examples include the Tiki Island King Windfighter torch, which claims it "Stays Lit In The Wind." Yet, the fine print cautions, "do not use in windy conditions."
A box of Royal brand instant pudding showed the flavor in big letters as "pistachio" with a picture of nuts in the green dessert. The fine-print ingredients reveal the nuts are diced almonds, the flavor artificial and green color from yellow and blue dyes.
A TV ad for Western Sky Financial offered loans of up to $5,000. The small print says, "The APR for a typical loan of $5,000 is 116.73% with 84 monthly payments of $486.58." Notes Consumer Reports, "so if you take $5,000 and pay the loan back over seven years, you're out $35,872.29."
And be skeptical of sale prices. A 30 percent-off sale seems like a good deal, but you have to ask, "30 percent off of what?" Sometimes, it's off a full retail price the retailer never charges.
Q. What can I do to protect myself against mouse print?
A. Simple: Read the fine print and be skeptical of claims that seem too good to be true.
"The consumer just has to be watchful and understand that most broad claims are going to have some type of limitation, footnote or disclaimer," Dworsky said.
That's not always easy in electronic media. "You almost have to have a TV set with freeze-frame capability, so you can read the fine print when it goes by so quickly," he said.