Remember the practical rules that will inevitably govern the behaviour of any alien "visitors":
1. They will be predators by descent at the apex of their food chain. 2. They will be utterly ruthless in their attitude to any competitors. 3. They will put their own welfare before ours in all cases. 4. They will assume that we operate as a species to the same rules.
Just put all this alien contact stuff through that filter and just hope to God that the UFOs aren't alien.
Imagine being an astronaut, leaving your family and loved ones to travel for thousands of years to visit a planet who you know nothing of because of a biblical event on your world. That is the what these Sentient Alien people would have had to give up in order to come to Earth. Alien abductions on Earth are in fact done by people, all of them and involve Hypnosis/ drown rape in order to force the victim to believe that Aliens did it in order to hide rape and sexual assault.
"Trust me I know what I'm doing" Detective Sledge Hammer