The toggle for that notification is in the Maps app under Hamburger > Settings > Notifications > Your Contributions. (If you think that's buried, you should see

The toggle for that notification is in the Maps app under Hamburger > Settings > Notifications > Your Contributions. (If you think that's buried, you should see the developer menu.) The difference between 5m accuracy and 30cm accuracy isn't terribly important if you're just trying to tell what building someone is in, and it won't improve in-building accuracy. I can't think of anything sketchy that it enables that someone couldn't do already.