That's a bit of an old joke but a serious subject, nevertheless.
When I was in college in the early 1970's, my main means of commuting between NC State and my home near Fayetteville, NC was by hitchhiking. There were times that I would get a ride that would take me from just off campus to nearly my home doorstep. The worst case was during a snow storm when it took me 13 rides to go 52 miles ... and the last mile and a half was walking toting my suitcases with me.
As for picking up hitchhikers, I don't even give it a thought these days. While it is my nature to do good to others (Jesus teaches us, "as you have done it to the least of these, you have done it to me"), there are just too many people out there these days with no morals and no qualms about taking what is mine, including my life. I figure there will be someone much younger than I and, thence, a harder target than I, that will give them a ride. Sounds harsh but feels so much safer.