> Seems unlikely that whatever's driving the billboards in time square needs to have the mic on

There have been many interactive billboards in Times Square. Some of them are at ground level. The article even mentions this use case: "Those applications don’t even need to be obviously using audio; live visuals often use mic or line input to produce sound-reactive animation and the like"

> tiny bit of postproduction is a burden on the people making said videos.

What postproduction are you referring to? The dot is added to the video output by the Mac, not added to the video file. You can't edit it out.

> "Those applications don’t even need to be obviously using audio; live visuals often use mic or line input to produce sound-reactive animation and the like"

Why would anyone want to suppress a warning to the user that they are being surveilled?

They could simply set up surveillance cameras to watch all the people who can see any billboards with orange dots. Problem solved!

I can't make myself take this question seriously.

I think I'd love it if every billboard scooping up audio announced it was doing that.

If your billboard is recording me, I want you to add the orange light. Please please please please.

> What postproduction are you referring to?

Crop a 20 pixel column? Surely we have hardware that can do that in real time today...