So if I was willing to mute the audio for a while, I could have the map more quickly? I'm thinking of the case where I start losing reception of the station and want to find a replacement. By the time I'm looking, we're probably down to one or two bars and it's not worth listening to anyway.

Hmm, perhaps if the tuner is muted (or we're in MP3 or Aux mode), scanning could happen more quickly. Otherwise, it could build up gradually outwards from the current position, the way that MP3 Seek Tool builds up gradually from the left (beginning) of a previously-unplayed track.