Interesting, in some of the reports of alien grays (and the Gnostic texts from thousands of years ago about the "Watchers", who seem to be some type of alien gray), that some are supposedly artificial life forms, so advanced that they seem alive, and yet they search for something that they think is missing in themselves but that we have. It's a real shame that the government (or their assigns) can't seem to learn from the mistakes of others, or apparently even their own mistakes.
There is even some evidence in the reports that the greys are us journeying here from the future, paying for the mistake of ruining the environment and their own DNA, and trying to undo the past before it's too late. Wouldn't that be a good reason that they don't want to make a big show of appearing everywhere in the open, because it would alter their own future timeline and they don't know how it would affect their present (our future)? It would also be a good reason that they are taking DNA samples and doing hybrid experiments, to try to repair their devastated, dead-end genetics. Hmmm, this line of reasoning is apppearing more and more like it would make a good Hollywood blockbuster. I wonder if Whitley Strieber reads this forum?