I realize that I am probably over paranoid and the likleyhood of something like that happening is small, but when I think about the worse thing that could happen in life...that's it. There is no way I could ever live with myself if anything ever happened to my kids. And the one thing you always hear from the parents of the kids that have been abducted or abused is "Oh, they were just playing in the yard while I went in to make a sandwich" or "little Billy walks to that friends house every day, it's only a block away".
So while the chances are slim, it does happen, and no one thinks it will happen to them...and that is one thing in life I am not willing to gamble on.