The other possibility that occured to me is tv programming shipped out to various military bases around the globe. I once came across at a thrift store 16mm prints of filmed tv shows with Navy markings on the cans. Back in college, the tv studio I slaved at used to get donations of U-matic tapes in Navy Blue shells with U.S. military markings on them. The few intact labels often listed tv shows with airdates from 1979 into the mid 80's, but they were usually all bulk erased!