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.
"You'll never take me alive" said he, And his ghost may be heard if you pass by that billabong "Who'll come a Waltzing Matilda with me?"