When you have a sighting (I say when, because more people are witnessing them, and your chances are good in seeing one), you'll either be excited or spooked, I've noticed people do one or the other. And as for being visited by people from another world or dimension, well, a lot of ancient cultures say they met them and they will return. This indeed would account for the multitude of sightings we have today, they may be gradually letting us know they are here.