I'm going to have to try to experiment with this a little, but I had this weird occurrence today when my Volt was charged at home but sitting with the cord plugged in. The car finished charging the previous evening and I had turned off the smart plug, but I didn't get a chance to unplug it. One full day later, I unplug the cord and I forget to unlock the doors. The cord theft alarm didn't go off immediately. 5 hours later, my car alarm goes off and I get the Onstar notification about my cord.
I kind of vaguely remember reading in other threads about how the Volt can go into some sleep mode. It just seems weird that an event like the charge cord alarm doesn't wake it immediately. In all of my previous charge cord alarm cases, the car was actively charging and the alarm went off right away.
If I had not turned off my smart plug, I'm guessing the car would not have gone into the sleep mode and I would have had the alarm go off immediately.