Good point Frono.
The temperature difference between the most recent time in transit and temps in the delivery truck would need to be very similar to the temperature at the final destination in order to safely immediately open the case for inspection.
I guess shipping is always going to be more or less a "crap shoot".
Pay your money and hope for the best., eh?
MD
In transit temps shouldn't matter, as temp changes would be gradual to the instrument in a well packaged case. Not to mention, well build instruments are much more resilient than you'd think. The main thing to avoid is very sudden 30+ degree changes in temps
to an exposed instrument. Touring bands have for ages loaded their gear in cargo holds under tour buses, in pull behind trailers, and on cargo holds of planes ,etc. None of which are climate controlled. They go everywhere from 100+ degree temps in the south to -20 degree temps in the north. The only rule of thumb is leave it in the case for an hour or two to acclimate after you bring it inside.
If you have to sign for it, just ask the driver how long it's been in his truck. If for even just an hr or two, and the truck's cargo is not far off from outside temps, I'd have no problem opening it for inspection right in my driveway. Even if it was 35 degrees outside. Then I'd close the case, bring it inside, and wait an hr or so before opening it again. Good guitars are tough. I fear dry heat much more than the cold w/ acoustics.