I like that there are a few angles to see the greys as, as imo, awareness comes in steps, and also as Q states: multiple meanings to all.
greys from the 40,000ft view and above= AI minions of the lizards >>1901080 ←–(this post Aeye related)
Greys as in foo fighters (craft) http://www.area51.org/foo-fighters-ufos-in-world-war-ii/
Greys as in the "grey man" >>1889446
Greys as in the security company anon just posted >>1981762