In another, a cooked chicken was advertised on sale for $6.99, but the original price of $11.99 was charged at the checkout. In this case, Pickering said, the mistake was spotted and the customer was given the chicken for free. But more often, retailers respond badly when errors are pointed out. Shoppers who took part in the study reported sales people "rolling their eyes" when asked for a refund, having to fill out forms to get a $2 overcharge returned, and being offered cash refunds only when the original purchase was by credit card. "The errors are happening right across the retail area, particularly large-scale stores," Pickering said. "When you're pumping 100 items through a till, it's much easier to make a mistake and much more difficult for the customer to keep up with the things flying through the scanner."