jhoglesr - Sounds like I should have just RTFM, right? Now that you mention it, this is indeed what that feature seems to do. I think most would agree that the way the function is presented on the interface, is confusing and misleading.
Adam - I will tell you exactly why it's an issue. I was navigating to a club in downtown Houston last weekend with my wife. I DID NOT need the AVIC to remind me not to take each major freeway exit ("in 7/10ths of a mile, keep left," etc., once every two minutes). When I got into the area, I wanted to turn up the volume AND apply the muting so I would be alerted to my exit. While trying to adjust TWO settings on the AVIC (amidst busy downtown traffic, no less), I missed the exit. No, I didn't understand the exact functions of the settings at that point, but this is what happened, and what could easily happen again. If you simply turn down the volume, you still get the muting, meaning that you have TWO settings to adjust if you're like me and like to have interruption-free music AND silence during voice guidance.
Also, I make frequent road trips along the same highway and want to set a destination to know my ETA and miles to go. I DO NOT need the voice and a simple on/off would be much better than the volume thing.
Well, clearly my poll was misguided, and thanks for clearing it up, j! Maybe Pioneer will make some improvements on the interface next time around. There are PLENTY of things they could have done better on the AVIC, much as I like it overall.
Cheers!
:)