I have had this happen once to me in PHUKET. I bought a bunch of items. The clerk scanned them. I looked at the total and just shook my head. A pause. I looked at them again, with a sour face and again shook my head. Another pause. Punch, punch, punch, a few buttons, rescan all the items... appx 100THB cheaper. I paid. Life goes on. I wondered how often that happens to tourists and the don't know.

But it's in SINGAPORE where I repeatedly get shortchanged at 7/11. A few times while I was talking on the phone during my purchase. $5 or $10 SGD each time. I habitually count my change everytime I get some. It's from 20 years of being a waiter... where any clerical error was paid from my pocket, if I made one. When it happens, after counting the change, I just put it straight down on the counter and point. The missing bill is then quickly tendered. Bloody crooks, it drives me nuts.