I once received too little change at a grocery store. I told the cashier and requested the dollar difference. Another cashier, who was shmoozing with her, told her (right in front of me), “She’s lying. She sneaked the dollar into her pocket. Don’t give it to her.” I protested, but I couldn’t even prove her wrong because I did have another dollar in my pocket.
In the end, the first cashier gave me the dollar, but I felt horrible.