This could be very bad in an emergency. If you are hiding from an active shooter, for instance. You couldn't silence your phone in a bag.  

One very memorable thing a college professor told us was that if we decide to teach or entertain,we will be competing with a world of electronic communication that offers thousands of options potentially more interesting. You will have to get, and keep, the attention of your audience or your students. This was a sobering conversation for many of us.