If you are right about the technology these aliens have, then it stands to reason they have transporters like in Star Trek. They should easily be able to collapse the wave function of one of their own and send "it" to some other location. No need to zip around our skies so much. They can just park themselves in orbit. They'd also have sensors like the Enterprise that could tell them everything they'd need or want to know about the planet. And how many damn cows do you need to mutilate before you have everything you need? I don't know. If you're right, it throws into question a lot of presumptions about aliens.