It seemed at one point that there was a lot of confusion about what the ring/silent switch on the iPhone and the side switch on the iPad should do. At the time I recall not being able to discern a clear distinction from Apple, but this week when asked about it again I was able to find clear direction in the current manuals for both device types. To quote from the iPad mini's manual:
The Side Switch doesn’t mute audio or video playback. Use the volume buttons on the side to silence these sounds.
If the device is muted/silenced by the switch it is supposed to only silence incidental sounds, however if sound is the primary purpose of the experience, then that should still be heard. It is one extra attention to detail thing when developers understand and make their apps obey this.
Another thought on audio in apps, specifically games, it is surprising to me how many don't allow me to listen to my own music while playing. Many get it right, but there are a couple that incorrectly setup their audio session, so even with sound effects and music turned off I can't listen to a podcast, or another uses a movie when launching the app, but the movie doesn't have any audio, but it still stops playback of my own audio.