I can't think of anything in a standard mattress that would preclude you from 'normal' bending at 5 or 10 degrees below zero (that is to say, if it can make that corner warm, then it can make that corner 'frozen')... but then I'm not an engineer or materials specialist :-)
I've never heard of our guys using that excuse and they are masters of excuses!
Are there some sort of gel pack in there? I assume it was still sealed in plastic and therefore dry. (I supposed a high level of moisture, if frozen, could cause fabric damage or stretching when manipulated.
.. going out on a limb and calling BS on these guys :-)
It's just a foam mattress with fabric padding on the outside, and it was encased in plastic so moisture shouldn't be an issue. These guys deliver mattresses exclusively so they may base their decision on problems that are extremely uncommon. They were complaining about our long rural driveway, which predisposed all of us to feel grouchy from the start. (I felt bad about it later.) They'd phoned from the road to ask if we had a turnaround, which we do, but they didn't mention the huge size of their truck, which would require some careful maneuvering in winter. Some truck drivers could have done it but they just backed all the way out.
I have confirmed from the 'Pro' on my staff that a high end memory foam mattress could get a permanent crease if folded in half but they usually 'bounce back' in a week or so (apparently crease doesn't happen with cheaper makes?) He also told me that they would routinely leave the memory foam mattress in the garage as long as possible in winter before moving it, because if it can freeze up it's easier to manage. (when they are warm they wobble all over and rub walls etc)
Interesting, thanks for the info! Ours is only medium-high end but it probably still applies. It didn't need to fold to get up the stairs but we had to squeeze the top down 20 cm so it bowed out to the side. As your guys said, it was kinda floppy and very hard to "steer"!