That would result in a much larger payload, and a payload size that is variable depending on how long it has been, and how much audio was record-able between requests. But if instead we observe a small payload of constant size given the same request, regardless of how long between requests, then we can reasonably be assured the device is not doing this.

Or you can be reasonably sure the device is only sending a payload of max size N at a time, padding your requests with some recording data when it can

Any smart tv could be doing the same thing. Why do you think that Amazon in particular is likely to be conducting a massive, secret and illegal surveillance operation?

>Any smart tv could be doing the same thing.

And many have been found to, which kind of proves my point.

>Why do you think that Amazon in particular is likely to be conducting a massive, secret and illegal surveillance operation?

Uhm, because it makes money? Isn't that the answer to any "why" in our current economic system?

Many smart TVs have already been found to spy on you. Which answers your question.

How do we know your laptop is not doing this? Or your phone? Or your TV?

In fact, it seems more likely that your laptop would be doing this give that it probably has far more electronics inside it.

I would hope the researchers were competent enough to space out their explicit uploads with varying periods of noise, while also finding a decent approximation of how much data is uploaded per x seconds of audio.

Sure, Amazon could use all sorts of tricks to attempt to throw off reverse engineering, but it would be pretty hard to do so with a large enough set of tests.