Yeah, the "GOM". I find it's really only fairly accurate once you get down to the last 10 or so miles of range remaining. Beyond that, all bets are off...especially in winter. It makes range "guesses" based on how you drive. What screws it up is when different drivers are behind the wheel. Suffice it to say, my wife is no hypermiler.
This is the first winter that I've had some close calls - and the first time I didn't have enough juice left to make it home. My wife and I went out to our club for dinner, and though I knew I was cutting it close on round-trip range - I figured I'd just plug into a 120v socket in the parking lot since we were going to be there for a few hours. When we got there, the parking lot was jam packed because there was an event being hosted there. I tried to baby the car home on 8% remaining. Ended up being about 3 miles short. We took an Uber home, and invoked the free AMA car pickup service (as part of the membership). Oops.
My wife took the B to yoga last Saturday. For whatever reason, I didn't plug the car in the night before. She drove the car without looking at remaining charge. When she was coming back, had the "battery on reserve level" message. I came to get her, and we ended up having brunch at a restaurant that had a 120v plug I could plug in for an hour. Barely made it home. Of course, this was all "my" fault, but I digress.
I know this sounds like I'm a total noobie when it comes to driving electric, but I'm not. Between life's "shit happens" moments, and the car's winter range degradation, this sort of thing can happen to anyone.