Moving a user account will not prevent the user from accessing their courses and data. They will continue to be able to access their courses and teacher's and admins will be able to access their enrollment data. The user will login under a different domain prefix and users will need to locate that domain where the user exists to be able to change data on it in the future if needed.
Is there anything more I can do for you?
Thanks Brian. Are there best practices for how this should be managed with the teachers assigned to respective subdomains? For example, a student starts his course in Domain A, we move them to Domain B and his courses come along with him. But different teaches work in Domain A and Domain B. His old teachers will see his enrollment, but will the new teachers? Will they have to be manually enrolled to the new course with a single student?
Typically we see organizations keep the enrollments within the same domain that the user account is housed within. Sometimes that's not always possible. Your organization will need to determine what will be the best and simple management of enrollments, users, and their relationship with courses.
A teacher will be able to see students that are enrolled within their courses even if a student's user account is housed within a different domain and they are enrolled in the same course. If a teacher doesn't have access to a student's course via being enrolled in it, they won't have access to the student's coursework or their course data.