As an instructor I would like to prevent students from being able to watch back their own videos for a certain period of time. For example, if I am running an activity across a day with students participating at different times (i.e. Sarah at 9am, Jane at 10am, Bob at 11am, etc), I will often need to use the same questions/scenarios for each student and I don't want the students to be able to share any of that information with others. Of course they could verbally share that information - but making the video available would provide an extra layer of opportunity that we would like to avoid.