App to put your phone into silent mode automatically

Does you phone ring when you are attending an important lecture? If yes, there's an app developed by IIT Bombay students that puts your phone into silent mode automatically when you're in a lecture. The app is only available to IIT-B students because every course has fixed lecture timings and all you've to do is select the course. The app then sets the phone into silent mode whenever you're in the lecture.

The idea is quite nice; but wouldn't it be a simpler solution to put your phone in the vibration mode all the time? Even better solution would be to put up a ringtone that becomes louder as the time passes. What do you say?