Why would you even try to stop them in the first place? It's a waste of time if you do. Fraud and duplicity are as old as mankind itself. Better try to make people aware and educate them. Make them aware and help them that way. Punishing those who scam people is a must, sure (if you can), but we will never be able to stop all of them. It's much more dangerous to get lulled into a false sense of security. Always be vigilant.
As the saying goes: "prevention is better than cure" meaning we should try to prevent the damage caused by scams before they have happened because, after they have happened irreversible damage has already taken place. Also, just because you can't stop all of them doesn't mean you shouldn't try too. I'm all for the people who dedicate their time in helping people stay safe.