I assume you ask that because you are aware that any device with the capabilities of a smartphone can be made into a powerful surveillance device by whoever the entity is that has control over it.

I see variations of that argument very often. Its essence goes like this:

A: This is a proven threat.

B: But so could be this and that.

A: Right, could be.

B: But we can't get rid of them all, so let's just do nothing.

Here person B somehow convinced themselves that doing anything in that regard to be futile because they can't solve this class of problems once and for all.

There is a distinction between possible threats on one side and an existing threat based on evidence on the other side.

Any device with the capabilities of a smartphone can be nefarious, but doesn't have to be. Any Android device certainly is.

So I'd like to tell people to turn off their Android devices, but may they keep using their open hardware and software phone, because I don't see them as the threat, but the entity that controls their Android device.

They are most likely asking because the main competitor to Android devices also has an always listening assistant.

Capability, yes. Correct me if I'm wrong but I don't believe it's enabled by default?

Siri has been enabled by default since iOS 9[0].

[0] http://ios9news.net/setup-hey-siri/

The always-listening portion is not. Also “enabled by default” still requires active user consent and agreement to plain English privacy terms. It is a step that cannot be missed when setting up the phone.

"Voice Match", the always-listening functionality of Google Assistant, also needs to be enabled. It requires training to your particular voice in order to make it more difficult for someone else to try to access your information using the feature. When being enabled a warning regarding the potential security implications of doing so is presented.

I would agree with the open hard-/software point, but that does not at all answer why you are purposely not mentioning the second most popular phone OS.

Are you suggesting there's proof that Google Assistant on Android devices is always listening even if it's turned off in settings?

What is actually the correct way to do this?

I don't use Android myself (I use https://ubports.com/ - it's great and you should try it), but several times I've had other people ask me to turn it off, and the best I can come up with is just dragging the Google search box off the home screen. But there's no feedback to suggest it's not still listening, only that shouting "OK GOOGLE" at the phone no longer does anything.

Hopefully somebody else will reply to you because it's been a while for me and I forget the details. There are settings in the Google App itself, settings in your Google Account in general and also I denied the relevant recording permissions for various google apps.

I'm using Lineage at the moment. I'd like to ditch Android entirely but I'm not sure ubports is where it needs to be yet. Unfortunately the open non-Android mobile OS's seem to die before they reach maturity. Obviously it's tough on them if they're competing with an existing app ecosystem, as they are.

Flashing it with something that has no google services is the most correct way to make sure you are not being spied on.

Actually, nevermind, I'll just go home again. Its been fun meeting you old friend