Customer has a need to protect a specific attribute or several attributes on all users. Adding thousands of user is not feasible in the protection template.
Protection templates can be applied to an OU to protect all of the User objects in the OU. Instead of adding all the users, add the OU's that contain the users, then change the scope to "This object and all child objects". Configure the rest of the template as needed (protecting all attributes, or just specific attributes, etc).