Rat is a term used to describe an informant regarding criminal acts or enterprises.
Unless someone is commiting a crime in treework (such as stealing logs), then the term "rat" is innapropriate.
A "rat", stemming from the fact that rats jump from a sinking ship, is someone that gives up inside info on someone he works with or for, having been engaged themselves in the same illegal activity. When the walls are closing in, typically, guys in the mob do this as do others. Turning someone in for false advertising is just policing the industry. Much different.