Imagine a course with a boatload of user-defined variables. We need users to be able to exit the course in progress and pick up where they left off later, so “retain value between sessions” is checked on all the variables.
Now suppose a user wants to start over as if taking the course for the first time. She launches the course, sees the message asking whether to pick up where she left off or start over, and chooses to start over. But she doesn’t actually start over, because all the variables remain set from last time.
How can we detect this choice, so that a learner landing on the first page of the course after choosing to start over is actually starting over, but a learner landing there because she navigated back to it (or returned to it, if the first page is a menu, for instance) does not have to start over?
You could add an (empty) first page that resets the variables and goes to the next page automatically. Without a “Previous page” button on page 2 (the first content page) a user navigating through the course can’t reach it.
In the end the prompt just says “Do you want to go to the page you’ve left off or to the first page”. “Start over” isn’t the default text for the “Cancel”-Button 😉 It should be much easier to reset the variables this way manually than preventing the course from resetting them automatically in case you didn’t want to start over.
With regards to the LMS I know (moodle): The bookmark is meant to enable a user to continue a running attempt, i.e. to go on with the variable values already achieved. To start over I’d make moodle start a new attempt with all variables in their default values. Resetting the current attempt is not really something the LMS means you to do.