Yes they happen but you won't find them in high traffic popular centers. They are usually run in holes or anonymously through eBay etc. they are not next to Barnes or nobles or near them for sure. Plus big retail here is so more competitive that that most will go out of business if customers find out they're cheated. Not so in HK where I see a bit of communism and much worse consumer protection where sellers see themselves above customers, where what customer voices does not matter.
Bottom line it happens a lot more often in HK than in the US for sure!