Won't happen, so don't worry about it.
After Mr. Trump became President, 1/3 of the Galactic Council wanted to nuke Earth to put us out of our misery, another 1/3 just wanted to cancel their field trips here (with the motto, "Beam us up, EkUrgxDds, there's no intelligent life down here."), and the rest were asleep. So if you run across a Grey in the next few years, it's a dwarf in a costume.