I would throw my vote in for the art of "common-sense-do", mostly on the part of the parents.
Make sure your kids are playing in safe environments. Don't let 'em play where they are not being observed by adults; *know* their friends' parents. Get involved in as many of their activities as possible, and make sure that someone you trust is looking after your kids if you are not.
Teach your kids that NO adult needs help from a child, EVER. Yes, I know this is not always the case, but in most cases, it is. If an adult asks a child to help find a lost puppy/kitten/pet, or help find *anything*, chances are it's a ruse. Never take candy, offers for rides, etc. Point is, if an adult needs help, they can find another adult--not a child--and your kids need to know that.
Teach your kids that they CAN say NO to an adult if the situation doesn't feel right. Teach them about the "bad touch", and that just because the person is an adult doesn't mean they are right. Empower your kids to say NO if an adult asks them to do something that they know is wrong. After all, most molestations and abuse comes from "trusted" people.
Last, but not least, teach your kids the power of noise. If they are grabbed, teach them that they should try to attract as MUCH attention as possible. Scream, kick, throw things, whatever it takes. Bad guys are like roaches--they don't like the light, and they don't like the light on THEM. They prey on kids cuz kids don't fight back as much as adults. Teach your kids to strike all the areas they can WHILE screaming. Key is, be vocal. Let other people know that this situation isn't right.
Fact is, *nothing* will ever protect our kids 100%, no matter what. Kids are abducted from even the best of situations (I live in Utah, and the Elizabeth Smart case is a perfect example). However, we *can* teach our kids how to fight back, and how to get the help they need.
Above all else, *be* there with your kids. Know who they are with. Pay attention to their questions. Be their friend, even if they start telling you things you don't want to hear. It all pays off.
Sorry for the rant, but this is a BIG issue with me. Thanks for listening......
Peace--