Gravitational waves are small ripples created by something such as the collision of black holes. They were first theorized by Alebert Einstein a hundred years ago and just recently confirmed by scientists using the LIGO. This LIGO (Laser Interferometer Gravitational-Wave Observatory) equipment shows an advancement in these technologies as it can accurately detect the most miniscule changes in waves through space. This was such an impressive calculation of 1/100,000 of a nanometer that it seems that humans can do almost anything in the realm of remote-sensing and communications when it comes to waves.
While this technology is very impressive for detecting small changes in space, it also brings up the question: what else is able to be detected using this method? By default through using this technology, scientists must be aware of many different waves and vibrations that they must tune out of their calculations. Therefore, there is the possible ethical dilemma about this observatory being used for something like surveillance right here on Earth. The military is interested in what this technology can do and there is always some apprehension when military forces get something this powerful and accurate on their side. I think there definitely is some ethical concern using this technology for anything other than purely scientific research. However, it is very likely that this technology would have evolved either way, using the LIGO or not. So I think there is not much concern for this observatory in particular, as this technology was always inevitable.