Today Starship Congress 2017, among other things, will discuss the Alcubierre Drive with the participation of Miguel Alcubierre.
http://www.icarusinterstellar.org/starship-congress-2017-program

I'm generally skeptical of this possibility, but I would like, however, to evaluate possible signs of its performance. 

Since the Alcubierre Drive is a bubble of highly curved space, it should same as gravitational lenses around massive objects, distort the distribution of light rays.
More likely that these engines (if even possible) use a hypothetical intelligent inhabitants of densely populated star regions of galaxies.
Then should quite often be observed abnormally rapid and almost linear distribution of compact optical distortion on the background of dense star clusters on trajectory of the spacecrafts with Alcubierre Drives. 

In the entire history of astronomical observations are recorded anything even remotely similar?