I'm going to take this to my local PO and show them . I think I will open there as well in case it broken @shadetree_1
I do the same thing. Empty space makes it easy for the box to crush in during the transit also. I have gotten to the point of putting useless wood in a box just to back up the cardboard to help prevent a blow out.I noticed a lot of the boxes I get are not actually "full of peanuts" as the senders say. They have extra wood but lots of airspace so sharp corners everywhere bouncing around. As a general rule I fill my boxes with wood so that there's no sharp corners. I have lost track of how many boxes of wood I have sent including internationally and I have only ever had probably 3 boxes that have encountered a problem. For the overseas boxes that I cannot fill with wood I do fill them with real packing material to keep the box full and the wood from being able to punch through.
You can't avoid it sometimes no matter what you do, but I have gotten a bunch of damaged boxes and have sent very few. The packing or lack of it is what increases or decreases the odds of it getting damaged.
I have gotten to the point of putting useless wood in a box just to back up the cardboard to help prevent a blow out.