I've been told my card was declined once, at Market Garden on Billy Folly Road. They actually gave me a copy of the recipt that clearly said "declined". I freaked, called the card company, and got the same answer, that no charge had been attempted. I used the card successfully several times after this, and even at Market Garden. That's when I realized that their system gives them a declined message when it's down.

Some merchants may pull that as a trick to get cash, but I've never had that experience. Not to say it doesn't happen....