Faith-healing and law

   Faith -healing can harm people. The law ought to make it illegal for faith-healers to claim success, because they rely on misperception, not on science.They are trying to be as medical practioners without the authority. However, as a ritual we have to countenance it.
    How many people have they harmed? Many. Cases come up about faith-healing killing children. Their rights to health dominates over their parents'or custodians' right to  worship.
  What should the law say about faith-healers' practicing medicine?
  What do you suggest on how to  warn the public about faith -healing and exorcism?