One more for the knowledge base...
Today, I reversed my Karma out of the garage and waited for my wife to get into the car. I then noticed the key symbol had appeared on the dashboard and a box appeared on the large central display saying "Return key to car to restore normal function" (or very similar).
I turned the ignition off and waited until the lights on the PRND dome went out and tried to start the car again (yes, I had my key fob with me). No response. It was if the key fob was not present. I then went into the house and got my other key fob to see if that would work. Same reaction (i.e. none).
I could not lock the car with the key fobs. But opening car door resulted in the usual chimes and semi-illumination of the dashboard. The car simply could not "see" the key fob.
I had to go out for a breakfast meet, so I left my unlocked car on the driveway and took another car to breakfast.
When I returned two hours later, the ventilation system on the car was happily purring away and recognized my key fob, starting up just like normal.
I guess waiting for two hours is not necessary, but my experience suggests you need to wait longer than just the 45 seconds or so for the PRND lights to go out.
If the car had still be unresponsive, I would have pulled the BBP but fortunately that was necessary. I would certainly have had a dilemma if that had not worked because the car was in Park and I would not have been able to push it up the drive into the garage...
Just in case someone else experiences this...