This tech isn’t new, exactly, though it’s probably significantly more sophisticated now. I used to work at a company that used similar monitoring a decade ago. Theirs was (allegedly) triggered only by the motion of the vehicle, I believe DriveCam was the brand name. It sucked back then, I’d imagine it sucks worse now.

My guess with the reality of the situation is Amazon or their insurance company required installation of the cameras and a low-to-mid level manager somewhere noticed that singing was triggering them, so the manager told people to stop and eventually you end up with this news story. Amazon gets at worst plausible deniability and shitty things continue.