[openasocket]

Disclaimer: AWS employee, not remotely related to any Alexa work

From the public record you can actually be pretty certain that Alexa doesn't send anything back to Amazon other than actual requests (and false positives). There was a murder trial a few years ago where an Alexa may have grabbed some audio of the murder. A judge ordered Amazon to turn over anything they may have, and Amazon said they didn't receive any requests during that time period, and they don't get any recordings other than those requests. So Amazon has effectively stated, under threat of criminal prosecution, that they don't record anything other than those requests.