I submit it's the child's upbringing that predisposed her to be trusting with strangers, especially ones espousing a religious lifestyle.
Not that it's bad, but that upbringing did not include lessons in cautious discernment.
I know a woman who--under the umbrella of "her Christian charitable ways" has taken under her wing (and defended and forced her loved ones to hire, tolerate, or otherwise deal with) every loser that comes her way--she's like a magnet. And, they're not neccessarily homeless bums--they're people that through their own fault have burned relationship bridges and have no friends due to their own weird idiosyncrasies, people who keep losing jobs because they're prima donnas, teenagers with attitude that just need a good kick in the a55, etc. Most of these people have turned around and taken advantage not only of her, but of everyone else in her life that she's forced these "projects" of hers upon.
Maybe some street smarts are good to have in kids ---wasn't the girl who escaped her kidnapper a black city girl? Less gullible, less afraid to escape?