How to spot an investment scam

An suspected investment scam involving the sale of derivatives linked to gold has been uncovered in Poland (Wall Street Journal). Based on preliminary evidence the following lessons can be learned: (1) Always check out the credentials of senior management, (2) Do you really understand the investment? In this case I doubt that many - if any - of the investors understood the difference between physical gold and derivatives, (3) Unusual and high marketing expenditures.