> hitchhikers are thus more likely to be dangerous people.

Do you have any reference to support this? Or is it just personal fantasy? If you look at the fbi.gov article mentioned (I linked it in a lower comment as well), you may notice that the hitchhikers were most often the victims: The victims in these cases are primarily women who are living high-risk, transient lifestyles

That you nevertheless think this statement to be true - I think rather supports my point about it being a question of culturally conditioned fear and stereotypes.