I've spoken with many people who were scammed that were just plain old naive.
Once you are financially literate, you understand what the risk-free rate is, where investment grade corporates are, what you can reasonably expect to earn in equities over a long period of time, etc. Only after you understand that, do you realize that any investment promising returns over that, is much more risky or speculative, and likely using leverage as well.
Don't assume that everyone knows 25% is not a normal return for a safe investment. I've had many calls with financially illiterate folks who were shocked when I mentioned what they can reasonably expect annually from an "aggressive" portfolio.