By Lindsay Rogers Secret shopping is not a new concept. The practice dates back to the 1940s as a means for corporations to discreetly monitor internal ongoings, primarily within retail settings. In the years since, it’s evolved into an $1.5 billion industry, one that employs hundreds of thousands of employees — sometimes called mystery shoppers — who are routinely charged with entering brick-and-mortar stores under the guise of a normal customer in an attempt to identify things like poor customer service and the potential for internal theft. That said, secret shoppers are not exclusive to ret…