enforce naming conventions for page aliases by content type
Yes, this use case is covered under the Pathauto module. 

Essentially, you'll add a new Content patterns (from the admin UI in admin/config/search/path/patterns) for each of your content types with the following path pattern, my_type/[node:author:account-name].

As long as the user doesn't have the Administer URL aliases &amp; Create and edit URL aliases permissions, their created content path will be set automatically without being able to change the path.