> Turning off camera LEDs and recording video is an old hack and old news.

This.

Some of the linux webcam drivers drivers have had the option to specify the behavior of the LED via a parameter since way back, including turning it completely off.

I remember this was the case ~20 years ago.

One example (look for the led-option) https://www.kernel.org/doc/html/v5.1/media/v4l-drivers/phili...

This is straight from the documentation:

"But with: `leds=0,0`the LED never goes on, making it suitable for silent surveillance"