Amazon Echo and recording laws

So devices like the Echo Dot are connected to a server and every sound they pick up is recorded there. There’s currently a case where the authorities are asking for the recordings to see if there’s evidence of a murder. In states where all participants must be aware of any recording of conversations are these legal? Would guests in your home need to be notified that devices are picking up their voice and recording it?

From a New York Times article:

Note that “every sound they pick up” is not “every sound you utter”. Devices like amazon Echo, Google’s “OK, Google”, Apple’s SIRI, and Microsoft’s (whatever it is) don’t activate until they hear their startup word/phrase “Siri, …” and that keyword recognition is handled locally. (Otherwise, your Internet usage would skyrocket.)

Ok, but it’s recording for 60 seconds after it hears the wake word. That could include anything being said by anyone right?

It’s usually clear that the devices is recording/listening. The echo lights up, for example and you can also have it play a sound if you want.

This article implies that Amazon itself doesn’t retain the audio recording indefinitely post processing. I don’t think Amazon would want to retain all of the 60-second snippets it gets just in case one contains something useful.

Sure, but it’s not like anyone is going to be saying: “Alexa, listen to me kill my wife.”

No, but in desparation someone might, I suppose, say “Alexa, my husband is trying to kill me”

Which raises an interesting question. Is there one quick phrase you could utter that would cause Alexa, Siri or Google to notify someone as to the identity of your attacker?