I tried to use the "Marked Location" feature of my 9500ci for the first time last night. I wanted to mark the location of a speed trap, so I hit the Mark button, and it said "Mark this location?" I then hit the Mute button to cycle through the options. Just then the light turned green, so I had to take my hand off the control module and put it on the gear shift. The 9500ci timed out and went back to its normal operating mode.
A bit later on, I tried to mark a different location, several miles away from the first. I hit the Mark button, but the 9500ci said "Unmark this location?" even though that location had never been marked (in fact, there are no marked locations in the database as this was the very first time I had ever tried to use it). I tried to mark a location several more times (different location each time), but each time it asked me if I wanted to Unmark the location.
Finally I cycled the power on the 9500ci, and after that it allowed me to mark locations.