There is that consideration, but the flip side of this is what Billavista went through with his first vehicle as a result of that car sitting outside the dealership in winter conditions and the subsequent leak issues. There's a huge thread here on that one, and it was nightmarish. If it were me, I'd be running it for a while to get it warmed up and allowing any standing water to drain through the internals before storing it again for the rest of the winter.... just to be safe.
Standing water won't drain once it's entered the cabin. There are no drain holes inside the cabin. Once you get water in there, you need to address it quickly to avoid any problems down the road. Good news is that mildew doesn't grow very quickly in freezing conditions. Bad news is water doesn't evaporate quickly either.
I'm late to this thread but hopefully this information will be helpful to anyone who might come across it in the future.
The first area you'll see water is behind the rear seats on the floor, which is a tough spot since you won't notice it for a while. When the car is level, that's where water tends to accumulate when the top drains are overwhelmed or frozen over. There's a cross beam going across the width of the car except for the tunnel, which has holes in it toward the bottom. That allows water to drain back toward the rear of the cabin behind the seats, where it settles.
The good news is, the cabin can hold a substantial amount of water before any electronics are affected. I'd wager in the range of a couple of gallons before you start to touch the seat belt pretensioner, which should be sealed fairly well. Next will be the under-seat wiring harness (for the head rest speakers, seat heaters, and air bags), and then the throttle pedal.
If you ever see ANY standing water in the car, or wetness behind the rear seats, you have NO option except to pull the interior. That means center console trim has to come off, seats have to come out, and carpet has to come out. That is the only way to guarantee that you won't have any corrosion or mildew. The white pads underneath the carpets absorb water like sponges. Bring the carpet and seats inside to dry, vacuum out all of the water you can see, then crack the windows open and blast the heat for a few hours to dry everything else out, and you should be clear.
It is strongly advised that if you have to park this car outside in the winter, DO NOT allow snow to stay on the roof of the car after it has snowed! Brush it off thoroughly the moment it stops snowing. I would highly advise removing the sponge filters from the top drains for any extended outdoor storage as these will accumulate ice over time as snow melts and flows down through the top drains, and will start to block water from draining out of the top, which means it will start to trickle into the cabin.
