My first reaction was, "That poor robot! Hitchhiking is dangerous." Which is a sad commentary on human behavior. Power doesn't corrupt, it reveals; which is why men are less at hazard hitchhiking but less likely to get rides, and women have an easier time hitching a ride but are more at risk. The only protection a robot has is if someone regards it as another person's property (which it is, but it looks abandoned when posted beside a road) or anthropomorphizes it enough to treat it gently.
So there are actually two aspects to this experiment: how to humans treat robots, and how do humans behave when they are unlikely to be punished for indifference or even cruelty? The first is the primary goal of the experiment: can robots trust humans. My suspicion is no, so I'm surprised this one has lasted as long as it has. That's hopeful. But then some girls make it out of drunken frat parties without getting raped, so there is a luck factor.
I'm intrigued by the construction. This is a vaguely humanoid robot, in that it has two arms and two legs attached to a torso, sort of a head with two eyes, and so on. I'm also intrigued that the eyes are glowing red. That's a prevailing motif with robots. I think it's because people often consider robots to be a threat, and red is a danger color, and some predators have eyes that reflect red at night. So I would expect people to have a more negative reaction to a red-eyed robot than a green-eyed one. Thus far, however, the robot has survived. It was designed with a "rummage sale" aesthetic, so maybe that helps people think of it as cute, as something to be protected instead of ignored or exploited. Hmm, the chunky outline may help it read as "childlike" and activate some protective instincts.
It will be interesting to see what happens.