The following message has been sent to the USPS.
On Monday, January 3, 2005, I shipped 5 1-quart containers of Isomil infant formula to Tana (hurts98 on TwinStuff) in Davenport, IA. It was in the original formula box (which normally holds 6 quarts). In place of the 6th quart, I inserted an airbag and I taped the entire box such that the contents would not fall out.
I had wrapped the box in white paper and taped it on all edges with blue masking tape. 
I hand-wrote Tana’s address on the box and used an address label for our return address.
Tana received the box yesterday, January 10, 2005 without its contents. In place of the 5 1-quart containers of formula were six bags of chinese food.
When I shipped the packages on the 3rd, I took them to the post office on Six Forks Road in Raleigh, NC and handed it to a postal worker. She weighed the box (5-6 pounds with the liquid containers) and the shipping came to $12.04 (which can be seen on the postage sticker on the corner of the
package. It was sent parcel post with no insurance, because there was nothing breakable, therefore I did not feel the need to buy insurance.
From the point that I brought it to the post office, to the point that it was delivered yesterday, it was in the hands of the USPS, which means someone at the USPS opened a package which was not addressed to them (isn’t that a federal offense?) and removed and replaced the contents, then proceeded to deliver the package. Upon delivery, Tana contacted me asking about an error and took these pictures showing how “beat up” the box was upon delivery and the contents.
It’s very clear from the 6 bags of food … 
that it would not have cost $12.04 to ship. It was a USPS employee who calculated shipping, on a USPS scale (along with two other packages I shipped that day), so there is no question the contents were heavy and liquid. The USPS employee asked me if there was any liquid in the package and I replied ‘yes’ and told her what it was, so she stamped FRAGILE all over the box. Again, this would not have been necessary had I actually shipped chinese food!
I am obviously very perturbed by this. The formula in the box cost $5.99+ per quart ($29.95 and I have now reimbursed Tana her $12.04 which she paid me to cover the shipping costs (thus I am out $24.08 with nothing to show for it).
It makes me very wary of shipping *anything* via USPS if I cannot trust its employees not to open the packages and steal the contents!