I work in retail and every once in awhile, mistakes can happen. If the difference is small enough, I would not argue with the customers over the difference. Let them have it and let them think they got a really good deal. But if the difference is huge, it is really up to the manager/owner to come up with a reasonable price. Let say in a car dealership- if by accident, the "0" fell off a sign and a $40,000 car becomes $4000, do you honestly think that the dealership will sell the car for $4,000??
I think its human nature to want to take advantage of a situation like this because it gives them the "David VS Goliath" feelings.
http://www.competitionbureau.gc.ca/epic/site/cb-bc.nsf/en/00522e.html#falseScanner price accuracyThere is
no federal legislation governing the question of price scanning accuracy per se. However, some types of price representations that result in overcharges to consumers may be examined under the Competition Act. In addition, it should be noted that the Bureau has endorsed the Scanner Price Accuracy Voluntary Code, which provides participating retailers of four major associations with a mechanism to provide redress to consumers when there is a scanner error. When the scanned price of an item without a price tag is higher than the shelf price, or any other displayed price, the customer is entitled to receive the item free when it is worth less than $10, or receive a $10 reduction for more expensive items. The Bureau regards scanner price accuracy as an important element of maintaining consumer confidence.