[user_of_the_wek]

Does that mean the phone will not react to „Hey, Siri“ without a mic icon showing up in the status bar?

[jeffhuys]

“Hey Siri” is activated by the mic, which is always listening, but only for the key phrase. It’s not going through the OS in the traditional sense, hence the “light” only comes on when it starts to listen through the OS.

[alternatex]

As an Android user I think there's no way for Google to assist unless directly called upon.