The legal issues could become significant, but only if the claims of Frauds, Scams, and Swindles are untruthful.
Slander is an untruthful oral (spoken) statement about a person that harms the person's reputation or standing in the community - a.k.a. a "Defamatory" statement. Libel is the written or broadcast form of defamation, distinguished from slander, which is oral defamation. Because libel is a "Civil Infraction" (e.g. a "Tort"), the injured person can bring a lawsuit against the person who made the false statement.
However, it would be up to the "injured" party to prove that the statements were untruthful, that his or her reputation was harmed, or that their community standing was adversely affected. So, the claims of Fraud, Scam, or Swindle would have to be both truthful and fully documented.
Also, I think that the threat of a headline reading, "Alleged Swindler Harasses Autistic Victim" would be something of a deterrent.
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The mere fact that science may not yet adequately explain an object, event, or experience does not mean the immediate explanation should automatically default to a conspiratorial, extraterrestrial, paranormal, or supernatural cause.