[vhold]

That's a perfect example.

I can think of two incentives for the vigilant to stay silent in the face of a scam.

One, in the case of a company especially, they may want their competitors to walk into the trap.

Two, the risk of accusing somebody of being a scammer (that you haven't fallen for) is too great, you get nothing out of it, and risk being sued.

Although, in this case, where peoples' health was put at risk, it would be especially awful to not speak up.