By default, Magento 1.6 allows your website’s visitors or guests to write reviews for your products. there may be times when you want to disable their ability to write reviews. Disallowing guest to write reviews in Magento 1.6 is done through the Magento Admin Backend.
- Log into your Magento Admin Panel.
- Go to System ->> Configuration.
- Click on “Catalog” in the left side menu pane.
- Open the “Product Reviews” section.
- Change the “Allow Guests to Write Reviews” and the “No“.
- Click “Save Config“.