there is no reason to believe intelligent extraterrestrials will be at all polite -- predators and scavengers are the best guesses or to put it in the words of

there is no reason to believe intelligent extraterrestrials will be at all polite -- predators and scavengers are the best guesses or to put it in the words of Zoe: If we meet aliens they will probably rape us to death, eat our flesh, and sew our skins into their clothing – and if we're very, very lucky, they'll do it in that order