Sometimes it costs more to be right than to be wrong; often it’s better to allow your customer to be right even when they could be wrong and sometimes you need to accept something that’s faked in order to win in a larger way.

I like Seth Godin’s post for establishing a way to deal with fake coupons (esp since Google will now be making them searchable online):

"When I was in business school, we did the McDonald’s case. Part of our preparation was to go to the nearby McDonald’s with a stopwatch and clipboard. We walked in the door and stood just long enough to get noticed. Boy did those guys hop to attention. Then we went to another McDonald’s and performed the following experiment (please, please do not try this at home, just take my word for it). We ordered a milkshake and a Big Mac. Ate half the Big Mac. Drank half the milkshake. We put the Big Mac remainder into the milkshake cup and went to the counter, "I’m sorry, I can’t drink this shake, there’s a Big Mac in it." They gave us a new one.

Why?

Because McDonald’s didn’t want counter people making decisions about who to say "no" to. It was worth the expense of humoring idiots like my study group for the brand power of knowing that counter people didn’t alienate people on a sliding scale."

All this started when a Starbucks coupon got redistributed too often and Starbucks decided not to honor it any longer.

"Check out this sign posted at Starbucks today. It reads:

"An email offering a free Starbucks iced coffee beverage was distributed by Starbucks partners (employees) with instructions to forward it to their group of friends and family. Unfortunately, it has been redistributed beyond the original intent and modified beyond Starbucks control. Regretfully this email offer will no longer be valid at any Starbucks location effective immediately."

If I was going to embarrass employees and ick out patrons by design, I am not sure I could have done better. The McDonaldsization of Starbucks continues."

Seth’s second rule seems to work the best here:

"Rule #2: if something gets out of hand, and you made a promise, better figure out a way to keep it. This sign is an ineffective response.  If it were my call, I’d take advantage of the "one coupon per customer" presumption and put a little tick on the buyer’s driver’s license or similar… just enough to slow down the particularly egregious scammers (who in this case aren’t really scammers. Starbucks asked for it).

So find a way to validate your customer, even if they come into your store/business with a fake coupon.