Good point.
Again assuming a technological civilization, those phenomena would get somebody curious sooner or later.
It was just a speculation. Realistically, it is likely that if there was one solar system floating in that void, there would be at least a few other isolated stars within naked-eye seeing distance. Under good conditions, individual stars can be seen by the eye that are over 4,000 light years away.
And to get the wondering going, all you really would need is one...