Mystery shoppers. For some it conjures up images of private eyes and undercover detectives. That's fair. In Nevada, a mystery shopper is required to register with a firm that is in association with the Private Investigative Licensing Board. Somewhat funny, but true. If you shop, and I'm sure you do, you have probably bumped into someone on a shopping assignment. Did you notice them? Doubtful. Or you may have found yourself on the receiving end of an evaluation by a mystery shopper. Did you reali.