When someone becomes a member of your home, they get the same level of access to devices and settings as you do as the person who set them up. Far from ideal for this exact reason but that's the way it works currently.
Therefore, your options are essentially:
This is mostly a user to user community, therefore if this is important to you, I’d encourage you to also send this feedback directly to Google. You will not receive a response, unless Google need more details from you, however the team are still reading the feedback.
Thanks for lending a hand, @davidking and @olavrb.
@Deez, I wanted to follow up and see if you are still in need of any help. Please let me know if you are still having any concerns or questions from here, as I would be happy to take a closer look and assist you further.