So, our bathroom has a whole bunch of switches by the door. Two light switches, fan, heat, two non-functional. I accidentally hit the fan when I went in yesterday and it triggered a interesting line of thought. I went about my business with the fan running because our bathroom isn’t pitch black without the light on or anything. Left the fan running because I was thinking about scifi stuff. If there was a race of aliens with no sight but very good hearing, would they use fans or other noise makers to block the hearing of others? Walk into a bathroom and turn on the fan (or equivalent noise maker) so that others in the house/building can’t hear them. Sure, other aliens could probably focus and hear through the noise or whatever but that would be considered the same as someone in our society peeking in on someone on the toilet. So the noise-maker would be considered something like a curtain or window shade.
Now, granted, it would also deafen/blind the alien inside the room. So it’s not a fully developed worldbuilding concept. I just thought it was kind of cool that a miss with my fingers as I entered a room caused that cascade of thoughts to spill through my brain.