FBI lured maniacs to fake website
Actually, catching criminals "on live bait" is not a very common practice. This is not customary to do, because it is not entirely ethical and can be classified as an inducement of citizens to commit a crime. In this case, there was a real fraud, and the advertised video did not actually contain any pornography. However, under US law, any “attempt” to download child pornography is already a crime, even if this attempt is unsuccessful.

A similar technique is clearly recognized as successful. Published court documents show that the evidence gathered is ample evidence in court.

If this goes on, then in the future the feds may organize spamming with the offer to buy some illegal drugs at all mailing addresses, and arrest everyone who had the misfortune to click on the link.