[NBJack]

To be frank, as cool as that is, it is easy to overlook the same problem with drones: they are distinctively LOUD unless at a distance (and even then).

Would be interesting to corroborate whether unusual noises are associated with their arrival.

[dogma1138]

The sound signature is relatively localized and for ship to ship boarding it wouldn’t be difficult to mask it through an approach.

Sound doesn’t reflects well of water so if you can easily mask it by flying close to the water and quickly jumping over.