No one with a decent POS system will do that. Costco is an exception only because of their policy of allowing items bought on line to a local store.

The receipt is barcoded and once scanned, the refund goes back on the credit card that you used to make the purchase. Credit card merchant services fees run 1.5% to 3%, plus a service fee that can be up to a dollar (typically much less). If you return a $100 item that means it would cost the retailer $2-$3 in merchant services fees. Ain't happening.