— “There is no quarantine,” Alice read. “You’ve been deceived. The planet has been conquered by space pirates. Don’t believe them. Report to the Galactic Center. Destroy this note.”
K. Bulichev. “A Million Adventures of Alice”
If I had to take over a planet and carefully eliminate the population, I would make sure everyone stayed in their own little burrows, diligently isolated from one another. I would ensure the streets were empty and that people only moved around when absolutely necessary.
Then the gradual decline in the population won’t be noticeable, and those who are still alive won’t panic, be afraid, or resist, especially not with arms. The decrease in population can be masked by mortality statistics from a new, unknown disease. Moreover, the constant confinement of the population at home reduces the chances of the newcomers being discovered.
Under the slogans of “self-isolation” and “quarantine,” any research activity that could interfere with the aliens can be concealed. For some reason, observatories are also not allowed to operate during quarantine, even though the poor astronomers clearly do not suffer from close contact with other people.
UFOs are being reported in the sky in such numbers now that the Pentagon is forced to publish information about UFO sightings and acknowledge their existence.
What you need is not a gauze mask, but a tin foil hat. There you go.