Hey, you may want to clarify that you are comparing apples and oranges--ArcGIS Online or Portal named users, versus ELA or MCL licensing agreements that can have both per named user licensing (individually issued ESU codes) and organizational use Single Use License authorization codes that are used across the organization.
Everything is pretty clear that ArcGIS Online and Portal (and now ArcGIS Pro) do require a per-named user management.
Not the case at all for Authorization codes.
Stuart
Andrew,
You've got me more confused now. Whare are authorization codes? I help manage our 50 user ArcGIS Online for Organizations account and I'm unaware of any authorization codes for users. We add users to our organization but if they leave or quit using AGOL we delete them thereby freeing up that named user.
Randy
(better late than never)
Authorization codes are used to activate Esri products, like ArcGIS Desktop, Server, etc...
as well as desktop and server extensions. After you install these products, you have to authorize them for use with Esri via an Authorization process. There are a few ways to do that, the easiest being to create a provisioning file from one's My.Esri.com account (assuming you are an admin for your company)
They are not related to AGOL.