This presumes they have the same nasty survival-of-the-fittest kill-or-be-killed attitude as humanity. Our evolution kinda created that but it doesn't have to apply everywhere. I think it's entirely possible that alien civilisations could exist that are a lot more symbiotic.
We have a saying in Holland "the innkeeper trusts his guests like himself" which seems to apply here.
We have a saying in Holland "the innkeeper trusts his guests like himself" which seems to apply here.