Once the Count and the Contessa had a buy one dinner get one free coupon to a local Mexican restaurant. And a coupon is of course another name for a voucher. I ordered as I always do 3 shrimp enchiladas off the a la-carte menu. Because of a technicality ordering off the a la-carte menu instead of a dinner we were told are coupon our voucher so to speak was not good.
Now to me it was no big deal we're talking a Mexican restaurant where even with an appetizer the bill was probably less than $30 however imagine someone requiring a voucher for a service much more important than a free meal at a Mexican restaurant and then saying that the voucher was not redeemable because of a technicality.