Are shared permissions stored in the Plex database?

Good day everyone!  Long story short I'm working on a Plex admin assistant to help manage my ever growing library.  At the moment it isn't ready for beta testing but once I have something that I deem as stable I will let the community play with it.  Anyways, as any good sys admin knows user management is a crucial part of running/protecting a server.  One of the features of the program that I'm working on will tell you the last time that each user that you have shared the server with has actually watched something.  Thus far this function works great, however I haven't found away to account for users that have had their access removed.  Is anyone aware of a way to obtain information about user permissions, preferably, from the database or are user permissions handled strictly by Plex's website as opposed to each server?