As a parent, I've gotta say this article is very accurate - you hear all these horror stories, but when you think back to your own childhood you were off alone doing crazy shit with your friends by the time you were eight. And that was back when things were much more dangerous for kids - we played in abandoned or under-construction buildings, went off into the forest near town for hours (where getting lost was a real possibility), rode bikes clear across town, etc... and all without the near-ubiquitous cell phones.
Kidnappings are no bigger a threat now than they were when I was growing up, and I never heard of a single person actually being kidnapped anywhere near me. On the news, sure, but only once or twice a year (out of how many millions of kids who didn't?). In the "stranger danger" talks in school, yes. And these are good talks to have with kids, in the same way talks about other risks kids run into are important. However, unlike the other risks you warn kids about (look both ways before crossing the street, go to a doctor if you step on a rusty nail, etc.) the insidious kidnappers are more bogeyman than reality. They're far, far more likely to run into a stray/feral dog than a kidnapper, but we both play that down in levels of danger, and tell them less how to deal with the dog than the kidnappers.
This fear-mongering is bad for children, as well - if a parent is scared of something, kids will become scared of it, too. Usually kids will break out of the terror of something as they get older and become more comfortable around whatever they were scared of (pots of boiling water, broken glass, etc.). When it's not something they will encounter and learn how to deal with that terror may never pass,though. How much of the current level of parental paranoia over kidnappers is a holdover from when they were kids being told there was a kidnapper on every street?
We really need to move on from teaching kids to be terrified of unlikely situations - especially since it leads them to have badly skewed risk assessment abilities. This is what leads kids to freeze to death in cold weather rather than risk asking a stranger for help. We need to teach kids how to evaluate situations, and how to properly deal with it if it does come up, but not to expect it to do so unless it's actually is likely to. In our school they spent about as much time teaching us about the dangers of kidnappers as of drug dealers... and I think it's obvious which of those are actually more likely to be encountered.