"A businessman in Winnipeg got a bonus when he purchased a booklet of the 45¢ stamp.  Some extra stamps were folded over and he proceeded to use them until, with only one pair left, he thought he should keep it to see if it had any collectable value.  Several years later, he walked into our shop on a business trip.  There are light fingerprints on the gum and a slight bend on one stamp, and there is a crease between the stamps consistent with the folds over of a booklet pane.  It is now 3 years since the 45¢ booklet was on sale, so it is unlikely that more of this error will appear on the market.  A major error that is possibly unique."