lucy24 - 9:39 pm on Aug 30, 2012 (gmt 0)
The parcel wasn't shipped from a shipping account but posted as a normal parcel from a post office in another city. The sender and receiver address where printed on small custom labels.
Ah, like that. The post office may insist on a return address for packages. I know you can't just toss them in the nearest dropbox; if you don't have a postage meter you have to deal with a human at the post office.
Detour to usps.com leaves me none the wiser except that they do say explicitly that mail which is picked up from your location has to have that same location's return address. Something tells me your steroid vendors do not have their packages picked up at their actual location ;) and, similarly, that they do not have a postage meter account.