duh, unless you 'ask' them by pressing a button they have to be continuously listening to hear the 'hey zuckbot' or whatever phrase they use.

The whole 'hey siri/hey google/hey online bookshop/etc' voice activation thing needs to go. If you want to put it in your own house with a 'smart' speaker, that's your choice but it shouldn't be on phones/tablets/glasses/etc where it can be used to eavesdrop.