Why is iOS microphone notification not active while listening for Siri?

Question

iPhones listen for Siri without displaying a microphone warning in the notification bar.Only after Siri is activated does the notification appear. This must mean that the notification and the microphone are independently operated and not a true signal of whether the microphone is actually listening or not, no?Can someone explain how this feature works and why this is or is not an issue?

alphan0n · Accepted Answer

Here's a decent explanation: https://hackernoon.com/how-does-hey-siri-work-without-your-i...Basically the microphone 'listens' for an audible key using the co-processor, but doesn't 'hear' or record anything, there's no audio information being written to disk or memory.