I was mulling over this today during an idle moment.
If Lee was willing, how about a physical push "hush" button that goes into one of the PAW USB ports? So you push the button and the PAW either mutes, or swaps the verbal alert for a beep, for a settable period of time in the PAW software? It could appear to the PAW as a HID or serial input. It could be a panel mounted button, small button on a yoke, or perhaps any momentary button of your choosing (ideally momentary, doesn't matter is NO or NC). Could even light up when muted, and you could push it again to un-mute before the settable period times out.
Would be fairly trivial to sort something like that out pretty quickly, but only if Lee saw it as worth his time?
It would also be possible to have a mini mixer, that took PAW and a tablet (SkyDemon) audio input to a single output - again with the physical mute button. This could mute one, or both, for a pre-determined period or overruled by pressing it again. Or perhaps just duck the audio for the period, so it's there just quieter.
I guess it depends on how people mix their PAW and/or Tablet of choice (running their moving map system of choice) into their existing audio system?