Don, I think it was a joke-- a child who is a predator, from your thread title.
Yesterday I taught my kids about child predators
First, this cannot be taught in one day, and you can never be sure it HAS been taught. The parents of any victimized child will tell you that they thought their kids "knew" what to do and not to do, too.
Remember, teaching them via fear will not make them safe against skilled predators who attract via reassurance-- they simply don't act "scary." Teaching your kids to fear people is the last thing that will keep them safe. Teach them to be smart and powerful, and to trust their gut feelings.
But you still have to be watchful, yourself. These people lie awake at night dreaming up the tricks to get around any training children are given. Sadly, they devote more time and thought to catching kids than we do, to keep them from being caught. We all have the responsibility of supervising our kids closely-- it's OUR job to keep them safe, more than it's THEIR job.