Correct on temp but the payload will not be at peak altitude long enough to saturate to that temperature level. I have crewed on many of flights that were far less sophisticated than I as far as insulation and heating. Granted, most were using GoPros. I'm the only one I know that is using this model of Canon(SD1400). Knowing that recovery is not a sure thing, I'd rather try to make a $40 Canon work than a $250 GoPro.
Other CHDK cameras have certainly flown, see http://chdk.setepontos.com/index.php?topic=3766.0
I'm not aware of any low temp shutdown in these cameras, though I suppose it is possible. I'd think low voltage due to cold battery would be more likely. Note that the camera will likely draw more current when actually shooting, so it could sag below the limit even if the last recorded voltage was over.
At the risk of going of topic, I'll post the last two pics from my latest flight that I am referring to. I recovered the payload with everything intact this time. I apologize to the mods in advance.
Update: Couldn't bring myself to cut down the resolution to post here. So here is a google drive link of all the pics from Sunday's flight:
Don't apologize, we love to see that people actually do something cool with this stuff!