You can't shame a scammer into changing his ways. And, those emotionally invested in their purchase cannot be drug to the conclusion that they spent their hard earned cash on a counterfeit. Telling a collector his/her precious is a fake will only enrage them and retrench their claims of authenticity. Telling a counterfeiter his/her item is a fake just tells them they've been outed and gives them clues on how to make better fakes. You may be able to "save" a few unwitting dupes, for a while. But, people that will unwittingly buy fakes WILL- eventually- unwittingly buy fakes. Being s collector means KNOWING what you are buying. If you pay a premium for something before identifying what it is, you kind of deserve to buy fakes. Taking a chance on a "steal," knowing it may not be authentic is- in my estimation- different.
Ad they say on another forum I frequent "buy the knife, not the story..."