Upload & Sell: Off
| p.1 #12 · Canon may have lost my 5D MkIII... |
It's easy for them to tell and it's Canon. If the weight they shipped it out at was less than impossible to have included the camera, you'll get a new one. If the ship weight is correct, they'll have the carrier run the weight scans through the delivery to see where it went missing, then they will file a claim and get you the money for the insured value.
This should be the answer to the mystery. I'd immediately check the weight on the initial shipping record and see if it was different from what you received. If not, its probably proof that the camera was never in the box.