Idea: timed or "when-pressed" database lock

I would like to see a feature eather to lock the database after a little periode of time (e.g. 1 to 10 minutes), or/and to lock the database by clicking on a button like the enroll button to open the database (e.g. converting the "open" button to a "close" butten when database is already open or add an extra button to lock).