I do not recall this evaluator. Might be a mistake somewhere. Here is what we try to do for our proof-of-concept:
An Alfresco Share site represents a project. We have more than one projects running in the same time
The company has few departments, 4 of them are doing specific project related works, 3 of them are support departments
The teams in each department are assigned to different projects, and with different roles. In one project User A can be a manager (or responsable) while the same person can be a simple user of content in the other project. Because of this, I was thinking to use user role assignment per site/folder to show/hide the different actions. A user can have one of the three - manager, contributor, user - role. Since we try to use Alfresco to manage certain type of engineering documentation and our processes (the next step is Activiti process development/implementation) are rather specific, we were able to create action groups (from document browser, document details view) for each of the three available roles. The goal is to avoid confusion and to make sure that the system is simple enough for the users. If not, they wont use it!
I tried to use an evaluator to check the user role (isSiteManager, isSiteConsumer, etc) and use the disableAction in case the evaluator returns True. Unfortunately this was not working.
The easiest solution would be to remove the unnecessary actions for all the users. But we voted against this solution.