Just installed a Garmin with the traffic receiver cable in a 2012 CM.
I checked prior to installation and confirmed that the plug went off with the key removal.

I used a commercial kit and tapped into the power leads under the console for the lighter plug port.

I also read that if this plug has a cell phone charging in stays hot for several minutes, not a clue how it knows that!

But after a day of not driving it for a day the battery was nearly dead/flat.

Just how smart is this plug, has anyone else experienced this issue?

 

I often keep my TomTom GPS plugged into the front power port. As far as I know, it comes on with the ignition and goes off with the ignition.

 

My Garmin did go off and so did the power to the plug until I started using the Traffic Receiver Cable.
Appearently the current draw must be keeping it on, but that's really weird.