One of the aspects that has fairly consistently been an apparent concern to extraterrestrials is our use of nuclear fission (nuclear fusion is what powers the sun [which - to simplify - fuses hydrogen to create helium], and is very different). One comment on that from the chapter on Jujuolui Kuita in "Meet the Hybrids: The Lives and Missions of ET Ambassadors on Earth" by Miguel Mendonça and Barbara Lamb (pub. 2015 through Amazon CreateSpace, ISBN 978-1518741012 - my review here), which I found interesting is:
"There’s a lot of speculation out there, but I want to stay with what I know. I feel very strongly that ETs will not allow nuclear war. It affects things too deeply, at the subatomic level, and it interacts with other dimensions that are nearby."
I consider we still have to do our bit in terms of preventing nuclear war, but the comment is interesting.
