[mhaymo]

It depends how paranoid you are. If you believe your audio is so valuable that Amazon would create a separate hardware model for you and those like you, and would succeed in keeping that a secret, then yeah you still shouldn't buy an Echo. You will also not want any other always-on devices with microphones and network connections, like a phone or laptop. 99.9% people are not in this category.

[cool_dude85]

I think you may not be worried about targeted attack here necessarily.

Suppose for example that Amazon wants to know how many people talk about some topic or brand, and wants to sell that information, but they think that the mute switch will get in the way of collecting the data.

All it would take is a relatively small sample - maybe 1/1000 Alexas randomly built in such a way that the mic can't be muted - and they would be able to sell these aggregated statistics with reasonable confidence intervals.

Not that I think this is happening, but it is a possible reason I might not trust a single teardown, and it doesn't require worrying about a targeted attack against me personally.

[michaelt]

Presumably the threat isn't a targeted attack by Amazon, but rather that the the hardware mute will get 'value engineered' away in the future to save money.