Re: Hotword
Seriously? How often do you find yourself saying ' OK Google' in conversation. I have a Moto X and it's never once activated due to an accidental muttering of "OK Google".
Looking at the Moto X, no audio before the "OK Google" is transmitted since that is recognized in hardware. I haven't tried the browser plugin to see if it's significantly different. To be honest, I think Google are just covering the arse in case they get some extra audio.
If you're concerned about what you have transmitted you can listen to the actual data on the Google Voice & Audio Activity Page.
https://history.google.com/history/audio
Out of curiosity, do Samsung let you check and delete your search history from their storage and that of their third party service provider? How about Amazon and their Echo?