Interesting. I never knew there were actual options. Based on those descriptions, our dealer rigged ours to unconnected too. I like the power control to ignition option. That would be nice as I always automatically turn it on myself at that point.
I use auto on, but have it connected to same switch as my radio. I turn switch on for radio and unit comes on, but I know I can turn mine off too ... so I probably wired PC Unconnected ... I'll have to look