There's a lot of conjecture in this article. While I'm sure most voice assistant makers would love to be able to tag multiple voices simultaneously in realtime

There's a lot of conjecture in this article. While I'm sure most voice assistant makers would love to be able to tag multiple voices simultaneously in realtime and perhaps even in the background, it's simply not there in today's technology.† The Alexa works in a crowded environment because it has directional microphones and facing the Alexa makes a big difference. The Google Home assistant does differentiate requests based on voice pattern, but from my testing it actually only analyzes the word "Google". So person A can say "Okay", person B can say "Google", and person C can say "What's the weather?" and the Google Home will recognize person B (this might have changed since I did my testing, so don't quote me on that). All this said, yeah of course any company can spy on you, and honestly Alexa is the least of your concerns. Laptops have 1-2 microphones built in. Phones have 3+ microphones. A lot of monitors and "smart" TVs come with microphones. Your intercom system can be wired into, and you can most likely hack into digitally based ones as well. Don't even get me started on IoT devices from non-IT companies. A lot of malicious things can be done with technology today, but Alexa is most likely the safest device of the examples I gave. So yes – stay vigilant – but don't ignore the more obvious vulnerabilities in your home. † There are some examples that prove we will be able to get there eventually (like Honda's ASIMO which has a demo of three people asking for different things at the same time), but nothing of the like has been seen in uncontrolled/noisy environments.