Lectora: Prevent same lesson being opened twice.

Is there any good method for preventing someone from opening up the same lesson twice? Either in two seperate tabs / browsers or two separate devices and running the lesson at the same time.

Obviously, you could go the route of putting a variable into the database (1 or a 0) and when they're actively taking the lesson the zero turns to a one, and the lesson cannot be reopened while this variable is a one.

But this is strife with potential errors and loopholes to get around it.

 

Is there any other good way developers have come up with?