A reporter wrote a story on her inadvertent purchase of counterfeit stamps at a New York City deli counter.
She put them on envelopes which were later returned with a sticker that read, "Return to Sender: Counterfeit Postage."
Of course, the best way to make sure you have the real deal is to purchase stamps from a USPS retail outlet, USPS.com, a lisenced vendor, APC or contract unit. All of the approved shippers will have a sticker on their window to show the source of their postage.
Have you ever encountered counterfeit postage either in your postal duties or as a customer? Tell your story here.