My Google Home isn’t the best at figuring out if me (or someone else) actually says “Hey Google” or “OK Google.” Sometimes I’ll be watching a video where no one says anything remotely similar to those phrases, and the lights on my Home flip on. But I have noticed that most of the time, the lights turn off a split-second later, as the Home actually realizes that no one called for it (presumably once the voice clip is processed by Google’s servers).
Alexa can now double-check if you actually said a wake word was written by the awesome team at Android Police.