Yes but elementary decision theory dictates that the magnitude of a risk has to be weighed against the severity of the outcome you're risking. One in a million or even one in ten million is not that small a chance when you consider what it's a chance of. A week in the hands of one of these people is a long time; being quickly shot to death is, God help us, one of the least bad things that can happen to a child in these situations. And I don't think it would be very easy to quantify to what extent the number of these incidents is kept down by parental and societal preventive measures, so as an argument against watching one's kids (which Reason pushes hard, probably not unrelated to their veneration of Murray Rothbard who wrote that children are property and are owed no duty of care), it falls flat for me.
No where did I make any argument against parents watching their children. I am addressing the alarmist talk that has parents of young children thinking that they are the frequent targets of trafficking. They simply are not. Even the occasional stranger abduction of young children is not related to trafficking.
Being vigilant requires evaluating real, credible risks.