I am aware that it could potentially be done with the beforeRegister event and the nosendmail example but I have absolutely no idea how. Has anyone been able to achieve this?

The situation is like this:  I am running a student council election and I want to restrict the votes to one per student. I know that all students have an email address of a format "*@student.uni.edu", but not each student's email address.

Thank you so much.

UPDATE: After spending some time, I have developed a plugin for those that need it

github.com/technowhizz/LimeSurvey-RegDomainRestricter