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"