In the light of Al Jazeera America’s multipart investigation into multi-level marketing companies, what advice would a white-collar criminologist and former financial regulator like me give to consumers to avoid being ensnared? The good news, dear reader, is that you likely already know the two common-sense truths that can protect you and your loved ones from such schemes.

Rule No. 1: If it sounds too good to be true, run — don’t walk — away. The word you want to use if your friends, co-workers or loved ones propose such a business opportunity to you is “no.” End the conversation immediately and get away from the person making the pitch. Don’t say, “I’ll think about it,” because that will encourage them to try to wear you down.

Rule No. 2: You don’t need to know or prove that the proposal is a fraud to have reason to reject it. Leave it to the courts to determine fraud. You simply have to know that it is your money and that there needs to be a compelling reason for you to give your money to someone as part of a business deal. If a person pitches you about a “sure thing” that is supposed to pay you a big profit, you know that he or she is lying to you. You don’t have to prove to anyone that the proposed deal is a scam. Anything that sets off even the tiniest warning bells is a perfect reason to invoke Rule No. 1 and say no.

There are all kinds of multilevel investment programs that may be legal (or too difficult to prove to be criminal schemes). The law cannot effectively protect you from such schemes, but you can protect yourself if you look for these warning signs and if you follow Rule No. 1 if any of them are present.