Skillens, a jewellers in Co. Down, ran a Facebook competition in December - a like and share competition to win a diamond and tanzanite ring. A few days ago, they announced the winner and posted a photo of the winner and her husband with the prize. Only... oops, the winner, Lynda Speers, was commenting on the picture and she forgot she was logged in as the Skillens Facebook account!
You can see the screenshots and the awful "statement" released by the company here:
http://www.bitterwallet.com/big-stink-caused-over-lovely-ring-facebook-prize/61625
Makes you wonder how often companies do this and get away with it.