The number of people harmed by quack practices is unknown. Most such harm is not publicly reported because the victims are either too confused or too embarrassed to step forward. When regulatory agencies seek to prosecute quacks, the agencies have a difficult task getting hapless patients to testify in court.
Many quacks do such a good job of exuding sincerity that their explanations seem all too plausible.
Even when a suit is filed, there may be little or no publicity. The news media often decide that it would be unfair to the defendant to publicize the case until a jury verdict has been rendered. The attorneys instruct their clients not to discuss their case with anyone. Plaintiffs' attorneys fear that a judge might conclude that publicity interfered with the defendant's right to a fair trial. Defendants' attorneys want to minimize publicity that could damage the reputations of their clients.