When the "deal" (international postal agreements) happened, nobody could foresee a country sending 10000 packages for each package received. They guessed the ba

When the "deal" (international postal agreements) happened, nobody could foresee a country sending 10000 packages for each package received. They guessed the balance would hang close to 1:1, with the western industrial powers (i.e. major exporters) probably sending more packages than they received. Thus it made sense that USPS carries Chinese parcels for free, if China post carries US parcels for free in return.