I have found what I think is equivalent to the counter-factual mugging.

You come across a thread on 4chan with text like "You have been visited by the murderous dog of murder. Your mother will die in their sleep tonight unless you please the doggie with 'good doggie'" Do you reply or do you have reason to reply? On one hand you don't have any evidence on who is posting the post and whether they are actually being able to pull of the murder. On the other hand the message is highly unplausible. (One could argue that seeing several "good doggie" replies is social proof that somebody is taking it seriously enough (but the explanation that it is more lolzy to play along is more plausible)).

The logic of someone who replies (outside of the lol factor) is "meh, its quickly typed and it would suck to find my mother dead the next morning". Yet it means that anyone that makes such a "visited by" thread is guaranteed many replies. Someone that recognises this is doesn't think that much about how credible th threat is. She just recognises the mugging and ignores the thread.