Embassies worldwide often mail letters (party invitations, a check to pay for power, etc) using the postal services of host countries. The vast majority transm

Embassies worldwide often mail letters (party invitations, a check to pay for power, etc) using the postal services of host countries. The vast majority transmit anything sensitive by diplomatic courier. I suspect in this case the document was simply placed in an envelope and not actually mailed, while the individual responsible didn't realize the consequences of using an branded envelope.