This just doesn't make sense. All electronic equipment has both operating temperature ranges and storage temperatures. The storage temps are almost always wider than the operating temperatures. Most industrial electronics have storage temperatures between -40C to 70C. Operating temperatures are much narrower, more like 0C to 40C. If your car trunk is in a Canadian winter and sits outside for 3 days, you could get -40C. If your car trunk is in Arizona in the summer, you could easily get well above 40C. But as long as you let your electronics adjust to room temperature before you use them they should be fine. Do you really think the ships and trucks used to ship your electronics are temperature controlled? The equipment sets for weeks/months in those on the way to you from their overseas manufacturing facilities.
I would have no problem at all leaving my machines in my trunk in the cold. I would be more cautious in hot weather though, and I would give them a number of hours before I turned it on. By the way, can you tell I manage electronic development programs?
Pam