Interesting question. To add to it, if indeed it is so easy for people to be misled into believing they saw things that they didn't, what does that say about eyewitness testimony in court used to convict suspected criminals?

We discount people who make extraordinary claims because their claims contradict our understanding of the world. But if some percent of eyewitness testimony is totally fake even when it is unbelievable, shouldn't we also discount testimony at an even greater rate when it doesn't contradict our worldview? Or are we to believe that this particular tendency to see things that didn't happen is limited to aliens and not run of the mill murders?