Starting 13 January 2021, Google's smart speakers will receive a Google Assistant update that brings a feature called Guest Mode. When this happens, your speaker will recognise when you say, “Hey Google, turn on Guest Mode". It'll immediately stop acting like your own personal assistant, no longer saving queries to your Google account or accessing some personal data such as your calendar.
It'll still be able to answer questions, play music, and set timers, of course. But data from those queries aren't saved with Guest Mode. It's sort of like Incognito mode in Chrome. That said, your speaker still needs to be connected to your account to serve up integrations you’ve enabled.
Google Assistant's Guest Mode simply allows friends to use your Google speakers without your personal data getting in the way. Just remember the feature doesn't securely lock down your data from prying ears, as turning off Guest Mode is as easy as asking the speaker to do it.
When you turn on Guest Mode, you'll immediately hear a special chime ring. You can then confirm "is Guest Mode on?” - with the feature staying active until you disable it (“Hey Google, turn off Guest Mode"). On smart displays, you will see a blank profile when Guest Mode is enabeled.