The following workaround solution serves me well, though on my 4th generation iPod I normally allow ("suffer") only these items to sound audible alerts:
- Calendar
- iMessages
- iOS: Low Battery (20% of remaining battery alert)
- iOS: beep when starting to charge
Another relevant aspect is that I have gotten very used to seeing the same Apple-supplied wallpaper design on my Home Screen, probably starting from late 2011 when I upgraded from iOS 4 to 5.
I needed a way to frequently switch the iPod to be silent and, equally importantly, to have a way to remember to switch it back later, to once again sound audible alerts.
That requires doing two things:
- Sounds > Ringer and Alerts: Set the volume slider all the way to the left (silent).
- Wallpaper: Temporarily choose a design that I would notice immediately, so I would know that something was different from what I consider to be the iPod's normal state of playing audible alerts. I chose one that
I consider rather garish, which naturallyattracts my attention. That leads me to rectify things quickly if I actually want audible alerts but the wallpaper indicates that I'd previously muted them. I change the wallpaper on the Home Screen only; you might choose Lock Screen as well.
Occasionally, despite my having muted the alerts, the iPod still sounds a quiet beep when starting to charge, which I imagine is due to a bug. That hasn't been a problem for me.
Normally, I put the Ringer and Alerts volume slider underneath the S in the Sounds screen heading, which is generally a good volume level for me. Periodically I need to set the volume louder than that, for which I choose another different wallpaper design, one which also easily catches my attention. That combination is the "Really Disturb" configuration.
I expect that the times when I forget to toggle the audible alerts appropriately with this workaround would still occur even if I were using a higher iOS version's official Do Not Disturb functionality.
See here for why I prefer iOS 5.