i pathologically pick up hitchhikers, and i agree that it's unlikely to be dangerous. not once have i felt like i was in an unsafe situation, though i am a decent sized guy. but there is a lot of "color" out there - old guys pressing me to get a hotel room with them and get it on, or people with bad drugs and/or tenuous grips on reality. my best experiences have always been around winter resorts - in my experience people hitching i70 in CO or tahoe in CA are almost always chill and pretty local. i'm still happy to do it, but i wouldn't really regard it as ready for prime time as the author.

for what it's worth the ride sharing apps, while interesting, don't seem ready to take the place of hitching in my mind. hitching serves a [casual||down market] segment that smart phone apps aren't ready to conquer (yet?).