How to make users avoid using Google Maps as a personal address book?

Adding private homes and fake places is never okay.

I would make sure they are not actually businesses with a strange name. And then go ahead and remove such places.

Learn more about cleaning the map here:

https://www.localguidesconnect.com/t/local-guides-clean-the-map-lgctm/271168

If you need more specific help, please share a few of the Maps links.