The practice continues today in designated areas -- here is the response to a frequently asked question from the Military Postal Service Agency's website:
Quote:
Is there "Free Mail" from the theater?
Yes, most areas of the Middle East have been authorized Free Mail for personal correspondence being sent from the service member overseas back to the U.S. Family members sending mail to service members in a free mail zone must pay for postage. Service members are briefed on the Free Mail procedures when they are deployed to a Free Mail area.