BlackVue's official app includes a world map showing the location of many of its dashcams, which users can tap to watch real-time footage. A red ring around a BlackVue logo on the map indicates that a dashcam is openly viewable to the public, while those without a red ring indicate a vehicle's location without footage. These appear to be from users who have opted in to sharing their location, but not their live feed.
Anyone who downloads the app and makes an account can view these livestreams, even if they don't have a BlackVue dashcam themselves. Free accounts are limited to 10 minutes of live viewing per day, though buying BlackVue's paid Smart subscription unlocks unlimited time.
The fact that it’s an intentional feature and not some bug or vulnerability makes this even more crazy.