Summary and Concluding Remarks
First, this experiment yielded a 64% delivery rate (18/28), an almost two-thirds success rate. (For our purposes, "delivery" constituted some type of independent handling by the USPS and subsequent contact regarding the object, regardless of whether we got to see or keep the object or whether it arrived whole.) This is astounding, considering the nature of some of the items sent. This compares with a 0% rate of receipt of fully wrapped packages from certain countries of the developing world, such as Peru, Turkey, and Egypt. Admittedly, those were international mailings, and thus not totally comparable; nevertheless, the disparity is striking.
Second, the delivery involved the collusion of sequences of postal workers, not simply lone operatives. The USPS appears to have some collective sense of humor, and might in fact here be displaying the rudiments of organic bureaucratic intelligence.
Finally, our investigation team felt remorse for some of its experimental efforts, most particularly the category "Disgusting," after the good faith of the USPS in its delivery efforts. We sought out as many of the USPS employees who had (involuntarily) been involved in the experiment as we could identify, and gave them each a small box of chocolate.
We, and all scientists, owe a debt of gratitude to these civil servants. Without them, we would have had but little success in pushing the envelope.