Heroku Postgres Follower

I’m currently looking at creating a follower db of a live production database. The follower will be used for analytics purposes only. And will not be inserting any data – if it did then it would be by mistake.

After reading the docs on heroku https://devcenter.heroku.com/articles/heroku-postgres-follower-databases#create-a-follower

I cannot see how you could prevent changes from a follower creeping back into the master db.

Any suggestions or pointers will be very helpful. Thank you.