Sting operations are good, but there are ofcourse bad ways to do it.
Like the one time, where the cops left a big van with its boot open and filled with new shoes in a poor neighborhood. That might be stealing, but its not in a shop, it might be abandoned and there is a small chance, that nobody will miss it(if somebody litterally just left it). That is a bit shady, but when it comes to setting up cars, sending out offficers to buy/sell drugs to catch buyers/sellers and proberly other direct-crime ways, its pretty good.
That said, i have never really heard it be used in my country, since we tend not to have rampant theft.