Somewhat off topic but also ironic - I recently upgraded my version of Android, and when I opened YouTube for the first time on this video it asked for permission to detect nearby devices. I get why it would need that to cast, but at this point it's not paranoia to think that granting that permission just means it would scan whenever I have the app open and upload the data to YouTube servers for no good reason.

YouTube can cast to TVs on a local subnet and is looking for them. This isn't new. What's new is that Android now warns when an app starts poking around on your LAN.