You know, wouldn't it be better to sue the creator of the facebook message for libel? Seems like targeting 'likes' is going after completely the wrong target, the person can't spread the libel if the libel isn't even there.
Here is likely what actually occurred...
The person who left the likes are someone they wanted locked up. They bent the laws over backwards to put them, and similar people, in jail/debt/whathaveyou.
Now not only is it illegal to make these claims but it is also illegal to respond to them in anyway.
So now a bad person makes a bad post... You can now go after all their supporters as much as you want.
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HOWEVER! I don't think the money charge is the real motive behind this. I mean it could be used as a method of dissuasion or petty "Well if I can get you some way"... But having additional crimes in a single event does very impressive things to the legal system.
For example "Breaking and Entering" is the crime of entering private property with the intent of committing another crime.
Tax Evasion is often used as a way of charging someone with a crime whose crimes you cannot prove.
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Or rather... if they wanted the people who handle Facebook to be charged, that is the angle they would have went with. Yet I don't think the impetus for this has anything to do with Facebook itself.