I use earplugs when going for long rides, but not for commuting, and I find it a hassle trying to change the volume when transitioning from earplugs to not - or vice-versa - especially due to the fact that the SMH10 maintains separate volume settings for each media channel. It would be great if there was a special way of turning the unit on such that it operated in 'loud mode', adding (say) 10 decibels to everything (i.e. all media channels and announcements) until the unit was switched off again. The advantage of choosing the mode as part of the turn-on procedure is that you would never accidentally leave it in the wrong mode.
(N.B. I don't know whether 10dB is a suitable value or not - I just picked a number. Maybe this could be a user-configurable setting via the firmware update program?)