A moderately amusing anecdote in this vein is that, when using the Oculus Quest headset, it has a passthrough mode which lets you see through the cameras (used to orient yourself or set up a virtual boundary). While in this mode, the controllers look fairly normal, but if you happen to glance at the controllers for someone else's Quest, you see these little lights on them. I always guessed that these were somehow related to tracking, but I was never sure of why they were only ever on controllers belonging to other headsets. Now my best guess is just that the Quest disables some IR lights on the controller to help mask some of the internal workings of the system, even though that's how it tracks the controller positions (since the only cameras are on the headset itself).
A moderately amusing anecdote in this vein is that, when using the Oculus Quest headset, it has a passthrough mode which lets you see through the cameras (used to orient yourself or set up a virtual boundary). While in this mode, the controllers look fairly normal, but if you happen to glance at the controllers for someone else's Quest, you see these little lights on them. I always guessed that these were somehow related to tracking, but I was never sure of why they were only ever on controllers belonging to other headsets. Now my best guess is just that the Quest disables some IR lights on the controller to help mask some of the internal workings of the system, even though that's how it tracks the controller positions (since the only cameras are on the headset itself).