"
Now, go and catch an alien to check how it influences the polarisation
of the photons, so next time you can recognise him.
"

Perhaps they have already found us and know much more about us than we think.

Perhaps they build a big photon cannon, which fires entangled photons throughout the galaxy.

And then their super computers keep track of all these photons.

Every time they bounce, or change this is detected/measured.

Perhaps this way it functions as a massive (3D) scanner.

They already scanning us ! ;) =D

Bye,
 Skybuck ;) =D