A commonly taught adage is to never accept a ride from a stranger. This applies mostly to children and goes hand in hand with warnings about accepting gifts from strangers.
Now, having grown older, I cannot think of anyone amongst my friends, associates or acquaintances that would ever willing harm a child by giving them a lift and stealing them away. Is riding with strangers truly unsafe for children?
To help define the question: How many child kidnappings (or other crimes) began by the child accepting a ride from a stranger? How does this compare to other kidnappings or other sources of danger for children?
The bonus question here involves hitchhiking, which is essentially the same thing but over long distances and usually by people much older.