Kohl's is the biggest offender of this. We used to go to Kohl's with my grandmother during sales and she would start peeling the price stickers. She trained us to never trust them because the lazier workers would just cover the old sticker with a new one and you could see the price was lower before the sale. Sometimes you could pull three or four stickers off and see the price increase, decrease, increase and increase again, it was crazy. But, because that's where she had the credit card and Kohl's cash she kept shopping there. Usually, the sales staff would be good about letting you have the whatever percent off the lower price you had uncovered though.