Force students to create account with right emails

[novoselt]

The problem: students create account with emails different from those listed in the course file and then wonder where is the homework.

The email invitation from the course system may have a link/button that will pre-fill the same email that was used in the course file and potentially will not even let the student to edit it. May help with students having multiple aliases that forward to the same inbox.

Any potential issues with SSO if this is implemented?