Store detectives can patrol the store wearing plainclothes and act as if they are real shoppers. They may browse, examine, carry, or even try on merchandise, while looking for signs of shoplifting and looking for possible shoplifters. Many large retail companies use that technique. Store detectives will watch a shoplifting suspect conceal an item, then stop them after they have exited the store. Those types of personnel must follow a strict set of rules because of very high liability risks. Many large retail or grocery stores have a store detective to watch for shoplifters. Most of those stores use secret verbal codes over the PA system to alert management, other loss prevention personal, and associates that there is a shoplifter. Store detectives must follow a suspect around the store by foot or by watching video monitors and observe every move the person makes so that they do not face a lawsuit for apprehending or arresting the wrong person.