While teaching Adult Learners in the on line and Face To Face (FTF), sometimes Adult learners have other Life situations. So you as the Instructor have to understand That disruptions in the Learning may arise. It is my opinion that Quizzes, Reviews Questions and pratice test should be able to stay in open mode.
As far as the Techincal level with each student for navigation there should be a avenue for each student to have and meet the schools platform requirements. I believe this would elimnate acessability fustrations.