Ford Sync and Reminders problem iPhone 4s
I do not think this is possible. I have a 2010 Fusion with Sync and no nav. The iPhone's ringtone is the only thing that will preempt the current audio setting if it is not Bluetooth Audio. Any other sounds (text message, reminder, turn-by-turn directions using Waze or MapQuest) are only audible if Bluetooth Audio is selected, a phone call is already in progress, or Siri is active. In other words, the phone's audio must already be playing to hear any alert other than a ringing phone. (caveat: I do not use Sync's USB or line-in connections for my iPhone.)

Privacy mode is when you manually change your call audio from Sync back to the iPhone using the audio sources button; the radio will display "Privacy Mode" and mute whatever is playing as long as you're on the phone.