Here is my situation, which raises my question and which may help in understanding it.
My testing center closes at 5pm. I don't want students walking in at 4:45pm to take their quiz since it requires testing center people to stay late or, if they don't want to stay late, the student will have to leave the testing center before finishing. I want to lock the quiz at 3:30pm. I am concerned that, if I lock the quiz at 3:30pm, Canvas might stop a student in the middle of taking her quiz. I am concerned that, for instance, if a student starts to take a quiz at 3:15pm, and if the quiz locks at 3:30pm, that the student will only have 15 minutes to take the quiz.
My question/s: if I lock the quiz, does that mean ONLY that students can no longer open it? Or does that mean BOTH that students can no longer open the quiz AND that they cannot continue taking it? If the quiz locks, would students in the process of taking it be interrupted?
Our testing center has a policy that will not allow students to begin an exam within a certain amount of time before they close and the communications with the students remind them of that. It really is on the student to plan their time.
As far as the Canvas side of things go, you cannot set the lock date before the due date. You want the due date so that things show up properly in the to do list and syllabus.
According to this lesson in the Canvas Instructor Guide, quizzes are automatically submitted at available until date. Students are unable to access the assignment once the available until date is met.