The customer probably won't notice and if they do they'll walk back to the place they found the item and find the e-ink price tag has a price that matches the till. If they some how dispute it further the business will just lie like a rug until a particularly pernicious customer takes pictures of the price tag and then argues with the manager.

The eventual outcome will possibly be a class action law suit and in a few years the customers can sign up to receive a gift card.

You can see similar behavior with the same company here: https://www.cbc.ca/news/business/loblaws-25-gift-card-class-...