How to disable Magento 2 reviews
Disabling the module on command line resolves in errors on different places. A better idea is to hide it with XML. Just create a child theme (if you don't have one already) like this:
How to create a Child Theme in Magento 2
and then inside your child theme create:
app/design/frontend/company_name/theme_name/Magento_Theme/layout/default.xml
and add this:
<page xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd">
<body>
<referenceBlock name="reviews.tab" remove="true" />
<referenceBlock name="product.review.form" remove="true" />
<referenceBlock name="product.info.review" remove="true" />
</body>
</page>
In Magento 2.0.2 you will get an error if you try what @MagePsycho suggested. You still can disable the module output by changing its status in the Advanced-Settings of Magento 2.
Shops > Configuration > Advanced > Advanced and search for "Review".
You might wanna flush the cache afterwards.
In Magento 2.3 Commerce at least, you can disable Reviews in admin at Stores > Configuration > Catalog > Product Reviews