It happened at Wal-Mart (Supercenter Store #1279, 10411 N Freeway 45, Houston , TX 77037 a month ago. I bought a bunch of stuff, over $150, & I glanced at my receipt as the cashier was handing me the bags. I saw a cash-back of $40. I told her I didn't request a cash back & to delete it. She said I'd have to take the $40 because she couldn't delete it. I told her to call a supervisor. Supervisor came & said I'd have to take it. I said NO! Taking the $40 would be a cash advance against my Discover & I wasn't paying interest on a cash advance!!!!! If they couldn't delete it then they would have to delete the whole order. So the supervisor had the cashier delete the whole order & re-scan everything! The second time I looked at the electronic pad before I signed & a cash-back of $20 popped up. At that point I told the cashier & she deleted it. The total came out right. The cashier agreed that the electronic pad must be defective. Obviously the cashier knew the electronic pad was defective because she NEVER offered me the $40 at the beginning. Can you imagine how many people went through before me & at the end of her shift how much money she pocketed?