If the Tensor security chip works on the Google side the same as Apple there is dedicated hardware specific to detecting the trigger phrases. No sound is processed at a software level until that security chip requests further processing at which point it shows the fake LED. The LED itself is added to the graphics layer in a way that cannot be hidden or obscured.

It is always a question of trust, but after more than a decade of phones they are pretty determined to earn trust. I have not seen any trustworthy reports of a secret always on microphone. Just the occasional recording made after a misheard trigger word or button which is an issue being further secured year by year.

Amazon on the other hand…