There should be a way to get the user_id corresponding to the access token and/or the BBID (UUID) through a get method such as "getUserByToken" or other. The endpoint could also return all id's of the accounts that the user has corresponding to its service, providing one endpoint to get all user_id's for each service corresponding to that BBID User.

This make it possible to use the OAuth protocol to obtain school api information about a user, instead of having to use the older SSO method as outlined in the docs, which seems to point towards the outdated ON API.