Jorah pointed out in the comments that the phenomenon (working to avoid unlikely but well-publicized risks) has in fact been studied. It's called the availability heuristic, which is probably something I should have remembered from psych 101 back in college. Click on the link if you want to geek out and read about it.
In any case, just to make it clear, I was in no way advocating intentionally putting your children at risk. What I was trying to point out is that if you spend all your time worrying about sensationalized but remote dangers (like stranger abduction) you're not only wasting your time, you're probably also ignoring many far more dangerous things that don't make the nightly news.