+1,000,000 on this!! That's why I made the comment above about filing such a claim being a waste of time/energy.
They'll find damned near ANY available excuse to refuse to pay a claim made. The piss-poor packaging job by the shipper, combined with a whole mess of other BS like "the item was not declared to be 'fragile' at the time it was entrusted to the USPS," and other nonsensical rambling to avoid paying up. While certainly a garbage job of padding/boxing up something by an individual or business shouldn't automatically become a financial burden of the USPS, the fact that they have a long-standing reputation as showing little to no regard whatsoever for packages shipped with them certainly doesn't give me any warm/fuzzy feelings when shipping items with them. For high-$$ items (like a $3.5k S&B for example), I'll skip the PO and stick with a different carrier.