Ditto. At Hardee's, we would never refund "short-changes" for more than a couple of dollars. $.50 to $.75 was almost always refunded without question, as there's always the possibility of drive-through person dropping a coin, or not actually picking it out of the tray. But to claim you were shorted a $5, or that we made a mistake on the bill was grounds for pulling the till. We were even trained to enter the bills paid with at the time, so a test run would take a minute (open the register, compare the number of 20's to the number on the printout, etc) instead of 15-20. Of course, if there was a variation (4 keyed, 5 in the slot, etc), or if the customer still insisted, we would call the customer after counting down our registers (either at close or after lunch, depending on how busy the day was). I can think of only a few cases where this happened (in 2-3 years), and only one or two resulted in customers being refunded their $5 or $10.
My advice, do something similar, but do it for small amounts (never more than $2-3 @ a time). This only really makes sense if the places are close together, however; otherwise, you might just spend more in gas!
