Dear harlots, always physically cover the microphone and the camera when they are not in use.
Do that even if you're just going to the toilet or heading to the fridge to get some snacks.
In use = you're seated there, consciously staring at the screen and interacting with whoever you're supposed to interact with.
This is a good habit to have, similar to checking for blind spots when you drive or cross the road, periodic checks on your personal belongings when travelling in a foreign land etc.